Search Results

Search found 14861 results on 595 pages for 'high speed computing'.

Page 501/595 | < Previous Page | 497 498 499 500 501 502 503 504 505 506 507 508  | Next Page >

• Remote paging with Nagios when network is down and email won't work -- cellular modems and alternatives

  - by Quinten

  What is the best option for remote paging when network services are down? I'm looking for a solution that can let me know when network services are down during off-hours only, and especially when email/smtp services are out. Therefore, it needs to be redundant to our network and power supply. I'm imagining a cellular modem is one option. What's the price range for these? Is anybody using them and feel that they are worth the cost? I'm imagining that it's something we would end up sending an emergency page ~ 1x/month at most, so I'd like the pricing to reflect that--I don't mind a high per-page cost as long as it has a low recurring cost. Another option would be to expose at least one server to remote ping, and run a check script on a remote server. Are there paid options for this? Currently, we run Nagios on a Linux VM on a Windows 2008 Hyper-V host. It would be great if the solution would work in that environment, but I know it's tricky with external devices, and we could move Nagios to a standalone workstation if needed.

  Read the article

• HP Proliant DL380 G4 - Can this server still perform in 2011?

  - by BSchriver

  Can the HP Proliant DL380 G4 series server still perform at high a quality in the 2011 IT world? This may sound like a weird question but we are a very small company whose primary business is NOT IT related. So my IT dollars have to stretch a long way. I am in need of a good web and database server. The load and demand for a while will be fairly low so I am not looking nor do I have the money to buy a brand new HP Dl380 G7 series box for $6K. While searching around today I found a company in ATL that buys servers off business leases and then stripes them down to parts. They clean, check and test each part and then custom "rebuild" the server based on whatever specs you request. The interesting thing is they also provide a 3-year warranty on all their servers they sell. I am contemplating buying two of the following: HP Proliant DL380 G4 Dual (2) Intel Xeon 3.6 GHz 800Mhz 1MB Cache processors 8GB PC3200R ECC Memory 6 x 73GB U320 15K rpm SCSI drives Smart Array 6i Card Dual Power Supplies Plus the usual cdrom, dual nic, etc... All this for $750 each or $1500 for two pretty nicely equipped servers. The price then jumps up on the next model up which is the G5 series. It goes from $750 to like $2000 for a comparable server. I just do not have $4000 to buy two servers right now. So back to my original question, if I load Windows 2008 R2 Server and IIS 7 on one of the machines and Windows 2008 R2 server and MS SQL 2008 R2 Server on another machine, what kind of performance might I expect to see from these machines? The facts is this series is now 3 versions behind the G7's and this series of server was built when Windows 200 Server was the dominant OS and Windows 2003 Server was just coming out. If you are running Windows 2008 R2 Server on a G4 with similar or less specs I would love to hear what your performance is like.

  Read the article

• What are the frequencies of current in computers' external peripheral cables and internal buses?

  - by Tim

  From Wikipedia, three different cases of current frequency are discussed along with the types of cables that are suitable for them: An Extra Ordinary electrical cables suffice to carry low frequency AC, such as mains power, which reverses direction 100 to 120 times per second (cycling 50 to 60 times per second). However, they cannot be used to carry currents in the radio frequency range or higher, which reverse direction millions to billions of times per second, because the energy tends to radiate off the cable as radio waves, causing power losses. Radio frequency currents also tend to reflect from discontinuities in the cable such as connectors, and travel back down the cable toward the source. These reflections act as bottlenecks, preventing the power from reaching the destination. Transmission lines use specialized construction such as precise conductor dimensions and spacing, and impedance matching, to carry electromagnetic signals with minimal reflections and power losses. Types of transmission line include ladder line, coaxial cable, dielectric slabs, stripline, optical fiber, and waveguides. The higher the frequency, the shorter are the waves in a transmission medium. Transmission lines must be used when the frequency is high enough that the wavelength of the waves begins to approach the length of the cable used. To conduct energy at frequencies above the radio range, such as millimeter waves, infrared, and light, the waves become much smaller than the dimensions of the structures used to guide them, so transmission line techniques become inadequate and the methods of optics are used. I wonder what the frequencies are for the currents in computers' external peripheral cables, such as Ethernet cable, USB cable, and in computers' internal buses? Are the cables also made specially for the frequencies? Thanks!

  Read the article

• How to find out what is causing a slow down of the application on this server?

  - by Jan P.

  This is not the typical serverfault question, but I'm out of ideas and don't know where else to go. If there are better places to ask this, just point me there in the comments. Thanks. Situation We have this web application that uses Zend Framework, so runs in PHP on an Apache web server. We use MySQL for data storage and memcached for object caching. The application has a very unique usage and load pattern. It is a mobile web application where every full hour a cronjob looks through the database for users that have some information waiting or action to do and sends this information to a (external) notification server, that pushes these notifications to them. After the users get these notifications, the go to the app and use it, mostly for a very short time. An hour later, same thing happens. Problem In the last few weeks usage of the application really started to grow. In the last few days we encountered very high load and doubling of application response times during and after the sending of these notifications (so basically every hour). The server doesn't crash or stop responding to requests, it just gets slower and slower and often takes 20 minutes to recover - until the same thing starts again at the full hour. We have extensive monitoring in place (New Relic, collectd) but I can't figure out what's wrong; I can't find the bottlekneck. That's where you come in: Can you help me figure out what's wrong and maybe how to fix it? Additional information The server is a 16 core Intel Xeon (8 cores with hyperthreading, I think) and 12GB RAM running Ubuntu 10.04 (Linux 3.2.4-20120307 x86_64). Apache is 2.2.x and PHP is Version 5.3.2-1ubuntu4.11. If any configuration information would help analyze the problem, just comment and I will add it. Graphs info phpinfo() apc status memcache status collectd Processes CPU Apache Load MySQL Vmem Disk New Relic Application performance Server overview Processes Network Disks (Sorry the graphs are gifs and not the same time period, but I think the most important info is in there)

  Read the article

• Is execution of sync(8) still required before shutting down linux?

  - by Amos Shapira

  I still see people recommend use of "sync; sync; sync; sleep 30; halt" incantations when talking about shutting down or rebooting Linux. I've been running Linux since its inception and although this was the recommended procedure in the BSD 4.2/4.3 and SunOS 4 days, I can't recall that I had to do that for at least the last ten years, during which I probably went through shutdown/reboot of Linux maybe thousands of times. I suspect that this is an anachronism since the days that the kernel couldn't unmount and sync the root filesystem and other critical filesystems required even during single-user mode (e.g. /tmp), and therefore it was necessary to tell it explicitly to flush as much data as it can to disk. These days, without finding the relevant code in the kernel source yet (digging through http://lxr.linux.no and google), I suspect that the kernel is smart enough to cleanly unmount even the root filesystem and the filesystem is smart enough to effectively do a sync(2) before unmounting itself during a normal "shutdown"/"reboot"/"poweorff". The "sync; sync; sync" is only necessary in extreme cases where the filesystem won't unmount cleanly (e.g. physical disk failure) or the system is in a state that only forcing a direct reboot(8) will get it out of its freeze (e.g. the load is too high to let it schedule the shutdown command). I also never do the "sync" procedure before unmounting removable devices, and never hit a problem. Another example - Xen allows the DomU to be sent a "shutdown" command from the Dom0, this is considered a "clean shutdown" without anyone having to login and type the magical "sync; sync; sync" first. Am I right or was I lucky for a few thousands of system shutdowns?

  Read the article

• Splunk is fantastically expensive: What are the alternatives?

  - by samsmith

  This has been discussed, but it has been several months, so it may be time to revisit it: Earlier discussion RE Splunk alternatives For the record, Splunk rocks. But the pricing is simply beyond what we can consider (When I spoke with Splunk today, the cost for a system to index 5gb/day of data is over $30,000.) That is more than we spend on SQL Server (by a large multiple), more than we spend on a rack of servers (by a multiple), etc. etc. The splunk sales team is correct (that for $30K we get more value and functionality than if we spend the same building our own system), but it doesn't matter. The splunk cost is simply too high (by a multiple). Soooooo, we are looking around! Is anyone out there building a splunk like system? Our basic need: Able to listen for syslog messages on multiple udp ports Able to index the incoming data in an async way Some kind of search engine Some kind of UI An API to the search engine (to embed in our console) We currently need to index 3-5gb/day, but need to be able to scale to 10gb/day or more. We do not need a lot of history (30 days is fine). We use Windows 2008 and 2003 servers. Thanks for your thoughts!

  Read the article

• Apache directory authorization bug (clicking cancel gives acces to partial content)

  - by s4uadmin

  I got a minor problem (as the site is not high priority) but still a very interesting one. I have an apache root domain wherein other sites live "/var/www/" And I have foo.example.com forwarding to "/var/www/foo-example" (wordpress site) The problem here is that when you go to foo.example.com you are prompted to enter credentials. If you hit cancel it gives you the access denied page. But when you go to the servers' direct IP (this gives you the default index page) and hit cancel when prompted for credentials it just keeps giving you the login screen, and after pressing cancel a few times more it gives (a perhaps cached) bare html part of the page. How do I prevent this from happening? Perhaps this is a bug... Even if I would block access to the root directory when going to the ip/foo-example it would still do this. And I want to keep all the directories within the www directory or at least all in the same. Thanks PS: here is my configuration: <VirtualHost *:80> DocumentRoot /var/www/wp-xxxxxxx/ ServerName beta.xxxxxxxxx.nl <Directory "/var/www/wp-xxxxxxxxx/"> Options +Indexes AuthName "xxxxxxxx Beta Site" AuthType Basic require valid-user Satisfy all AuthBasicProvider file AuthUserFile /var/www/wp-xxxxxxx/.htxxxxxxxxx order deny,allow allow from all </Directory> ServerAdmin [email protected] ServerAlias beta.xxxxxxx.nl </VirtualHost>

  Read the article

• How do I calculate the cost of printing a given page?

  - by Alenanno

  I have seen questions like How much does a square inch of ink cost and How much more will a high-dpi image cost to print?, but mine isn't asking neither about a specific case, nor about how much something costs, as that would depend on the toner, for example. Rather, I was wondering how should I go about calculating the cost of printing a given page. Note that "given page" should be seen as a sort of x, i.e. the answer should be applicable in any case; I'd like this question to provide a good reference for those who want to calculate this cost. What should be taken into consideration? The cost of a single page (the paper only) is easily checkable, since you divide the cost of the whole package for the number of pages in the package itself. But how do I calculate the cost of the ink/toner? Which could translate to: how do I calculate the Ink Density1 for a given printer? I know it depends on quality of the printer itself, the type, the quality of the image being printed, the very nature of what I'm going to print, etc. But again, the focus of my question is not on the variables of this case, but rather the constants, hoping the math simile works for this case too. 1: Total amount of ink in one area of the page.

  Read the article

• configuring lighttpd for large downloads

  - by ahmedre

  i run a web site that hosts pages that are just general scripts (php, etc) and mp3 downloads (some of which are fairly large - up to 200mb). i am running lighttpd on the servers on linux (ubuntu 64). everything is fine, but under high load, the server is not accessible (or very slow - even sshing in takes a while), and i am guessing this is due to a huge number of mp3 downloads at that time. consequently, dns sees the server as down and redirects all the traffic to the other servers, and after a while, it comes back up and things work again. so what's the best way to fix this? ideally, i want the server to continue running (and the web pages - php etc - to always work, but downloads don't always have to work). should i just have 2 web servers running (one for the downloads and one for the php pages), or is it perhaps something i can fix in my lighttpd configuration? here are the snippets from my configuration: server.max-worker = 4 server.max-fds = 2048 server.max-keep-alive-requests = 4 server.max-keep-alive-idle = 4 server.stat-cache-engine = "fam" fastcgi.server = ( ".php" => (( "bin-path" => "/usr/bin/php-cgi", "socket" => "/tmp/php.socket", "max-procs" => 1, "idle-timeout" => 20, "bin-environment" => ( "PHP_FCGI_CHILDREN" => "64", "PHP_FCGI_MAX_REQUESTS" => "1000" ), "bin-copy-environment" => ( "PATH", "SHELL", "USER" ), "broken-scriptfilename" => "enable" )) ) # normal php site $HTTP["host"] =~ "bar.com" { server.document-root = "/usr/local/www/sites/bar.com/" accesslog.filename = "|/usr/sbin/cronolog /var/log/lighttpd/%m/%d/%H/bar.log" } # download site $HTTP["host"] =~ "(download|stream).foo.com" { server.document-root = "/home/audio/" dir-listing.activate = "enable" dir-listing.hide-dotfiles = "enable" evasive.max-conns-per-ip = 1 evasive.silent = "enable" # connection.kbytes-per-second = 256 accesslog.filename = "|/usr/sbin/cronolog /var/log/lighttpd/%m/%d/%H/download.log" }

  Read the article

• How is made sure magnetic or electric fields from devices like transformers or fans close nearby do

  - by matnagel

  Fans and transformers which are inside the server case create magnetic and electric fields. Electric fields can be easily shielded, but what about magnetic fields, they can only be shielded with high cost materials like mu metal http://en.wikipedia.org/wiki/Mu-metal If a hard drive is installed too close to an intense transformer field, how is the magnetically stored information on the ferromagnetic surfaces of the disk kept safe? Even if drives are shielded, where are the limits? Is there some technical investigation or recommendation from manufacturers about this? (I never heard about something and never had any problem but I am interested in some facts. This is much preferred over what you believe or a habit you developed. Please try to give some solid infromation.) I have built and repaired many servers and sometimes I did put the harddrive on top of the power supply. Edit: This question is not about frequencies that could affect the drive via the power or data connectors of the drive, those are electronically decoupled and that's another question. Edit 2: The wikipedia page states that the motor inside the drive is shielded with mu metal. It is obvious that manufactureres have to take care of this. This question is about such influences from outside the drive.

  Read the article

• Docking Station Sound Doesn't Work on Dell D830 with Windows 7

  - by cisellis

  I have a Dell Latitude D830 laptop that is running Windows 7 Enterprise x64. I connect to a docking station during the day with multiple monitors, a keyboard and a mouse. Everything runs with no problems including most of the docking station ports (usb, monitors, etc.) However, the sound port from the docking station does not work since the upgrade to Windows-7. Even with the laptop plugged in, the sound always comes out of the laptop, not the headphones plugged into the docking station. Here's what I've tried: I've seen other issues like via Google this that seem to be mostly unanswered. I found one or two that referenced using the Vista x64 drivers, especially the Nvidia drivers. I do not have an Nvidia chipset but I've reinstalled the sound drivers and that has not helped. I don't have a support contract and considering the cost is usually high to call Dell, that's not an option. Dell's forums are pretty much a wasteland and I've found no help there. Since this is a docking station I thought I might need to try the SATA or Intel chipset drivers from the dell site instead, however I'm not really sure and I need to work on this laptop in the meantime. I can't really afford the downtime to experiment with random drivers all day in case they turn out to be incompatible (Dell still hasn't added Windows 7 to their support site as far as I can tell). Does anyone have any other ideas? Has anyone had this issue and solved it? If so, how? Thanks in advance for your help.

  Read the article

• This .mpg video clip doesn't play well

  - by Roey

  I've installed K-lite mega codec pack v6.9.0 with playback essentials without player. My default and only media player is windows media player. here are the clip's media info: General Complete name : D:\Users\Roey\Downloads\B384MV.mpg Format : MPEG-PS File size : 273 MiB Duration : 4mn 59s Overall bit rate : 7 643 Kbps Video ID : 224 (0xE0) Format : MPEG Video Format version : Version 2 Format profile : Main@High Format settings, BVOP : No Format settings, Matrix : Default Format settings, GOP : M=1, N=15 Duration : 4mn 57s Bit rate mode : Variable Bit rate : 7 363 Kbps Nominal bit rate : 9 000 Kbps Width : 1 920 pixels Height : 1 080 pixels Display aspect ratio : 16:9 Frame rate : 25.000 fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Compression mode : Lossy Bits/(Pixel*Frame) : 0.142 Stream size : 261 MiB (96%) Audio ID : 192 (0xC0) Format : MPEG Audio Format version : Version 1 Format profile : Layer 3 Mode : Joint stereo Duration : 4mn 59s Bit rate mode : Constant Bit rate : 128 Kbps Channel(s) : 2 channels Sampling rate : 44.1 KHz Compression mode : Lossy Stream size : 4.56 MiB (2%) Menu When I play it there is no sound (just a little "kahhhh" noise every 10-20 seconds) and the frames are moving very slow - it "jumps" frames. A blue tray icon [FFa] "ffdshow audio decoder" pops with the following details: Input:MP3, stereo, 44100 Hz (libavocodec) Output:PCM, stereo, 44100 Hz, 16-bit integer Any help will be much appreciated. Thanks

  Read the article

• Scaling databases with cheap SSD hard drives

  - by Dennis Kashkin

  Hey guys! I hope that many of you are working with high traffic database-driven websites, and chances are that your main scalability issues are in the database. I noticed a couple of things lately: Most large databases require a team of DBAs in order to scale. They constantly struggle with limitations of hard drives and end up with very expensive solutions (SANs or large RAIDs, frequent maintenance windows for defragging and repartitioning, etc.) The actual annual cost of maintaining such databases is in $100K-$1M range which is too steep for me :) Finally, we got several companies like Intel, Samsung, FusionIO, etc. that just started selling extremely fast yet affordable SSD hard drives based on SLC Flash technology. These drives are 100 times faster in random read/writes than the best spinning hard drives on the market (up to 50,000 random writes per second). Their seek time is pretty much zero, so the cost of random I/O is the same as sequential I/O, which is awesome for databases. These SSD drives cost around $10-$20 per gigabyte, and they are relatively small (64GB). So, there seems to be an opportunity to avoid the HUGE costs of scaling databases the traditional way by simply building a big enough RAID 5 array of SSD drives (which would cost only a few thousand dollars). Then we don't care if the database file is fragmented, and we can afford 100 times more disk writes per second without having to spread the database across 100 spindles. . Is anybody else interested in this? I've been testing a few SSD drives and can share my results. If anybody on this site has already solved their I/O bottleneck with SSDs, I would love to hear your war stories! PS. I know that there are plenty of expensive solutions out there that help with scalability, for example the time proven RAM-based SANs. I want to be clear that even $50K is too expensive for my project. I have to find a solution that costs no more than $10K and does not take much time to implement.

  Read the article

• Can I connect a Playstation 3's HDMI output to my monitor's DVI-D input? [migrated]

  - by HankJDoomstorm

  I'm attempting to connect my Playstation 3 to my computer monitor. The monitor has a DVI-D (dual link) input, so before distinguishing between the different DVI varieties, I bought a DVI-I (dual link) to HDMI converter that won't fit into the port on the monitor (not only that, there isn't enough physical space in the back of the monitor to fit that much stuff before it hits the bottom of it). So I grabbed a DVI-D (single link) cable and got a female-to-female DVI-I coupler, and plugged the DVI-D cable into the monitor and the whole mess of converters. The end result was HDMI to DVI-D single link, but my monitor isn't receiving a signal on its digital channel. (For clarity's sake: DVI-D DL input on Monitor, DVI-D SL cable, DVI-I DL female-to-female coupler, DVI-I DL to HDMI converter, HDMI output on PS3) I don't know much about this stuff (obviously), but my educated guess is that the bandwidth of the PS3 is too high for the DVI-D Single Link cable, so nothing's getting through. Will replacing the single link cable with dual link resolve this? If not, is it possible at all? Oh, I should mention I'm aware I won't get audio through the monitor. I have an RCA to 3.5mm converter for that.

  Read the article

• Switched from DVI to HDMI, possible audio artifacts?

  - by I take Drukqs

  I'm using an ASUS VH236H monitor and an EVGA GeForce 570 GTX both of which are brand new. My monitor has an audio out port for speakers/headphones so I plugged in my headphones and made a random selection from my library when I noticed two things: There are static-like artifacts during "louder" parts of songs. There's what seems to be a volume cap in place. When I crank the volume past 100% in VLC the decibel level does not truly increase but the amount of static does. The cable is not new; I yanked it off of my PS3 when my DVI cable broke. It has been used a good amount on my HDTV and PS3 so I doubt it's a matter of burn-in. I like the way the setup works with an HDMI cable as opposed to DVI because my headphones barely reach my rig whereas I have plenty of slack when they're plugged into my monitor. Thanks in advance for any support. Note: I'm using a high quality HDMI cable from monoprice, AKG K702 headphones, and VLC media player.

  Read the article

• Best usage for a laptop being used as a desktop without removable batteries

  - by Senseful

  After reading the information on http://batteryuniversity.com, I realize that one of the best ways to permanently damage a lithium ion battery is to use the battery at a high temperature while it's fully charged. This is exactly what happens when you use the computer as if it were a desktop computer, since leaving it plugged in will keep the battery at 100% and using the computer will heat up the battery. This is why it's recommend to remove the battery from your laptop if you are using it is this scenario. My question is what would you do if the laptop doesn't have removable batteries (e.g. a MacBook Pro)? Should I use some kind of charge cycle such as: charge to 80%, unplug the power chord, use the laptop until it reaches 20%, then repeat the cycle by charging to 80% again? If so, which values should I use instead of 80% and 20%? (I think charging to 80% is better than 100% because of the damage that a hot battery at 100% can do, but I just made the figure 80% up, and I'm sure there's a better number to strive for which is backed by science.) I've read many of the articles on batteryuniversity.com, but couldn't find anything pertaining to this. Update: What about doing something like charge (or discharge) it to 50%, then plug it in and turn on settings which use the battery as much as possible (e.g. brightness all the way up, wi-fi on, etc.), in order to try to maintain the battery at 50% (i.e. the rate it is charging is the same as it is discharging). This will probably heat up the battery, but would make it so you don't need to constantly plug and unplug the laptop. The one bad thing is that you are taking up more charge cycles which would decrease the battery life, thus I'm not sure this is a good idea.

  Read the article

• What performance degradation to expect with Nginx over raw Gunicorn+Gevent?

  - by bouke

  I'm trying to get a very high performing webserver setup for handling long-polling, websockets etc. I have a VM running (Rackspace) with 1GB RAM / 4 cores. I've setup a very simple gunicorn 'hello world' application with (async) gevent workers. In front of gunicorn, I put Nginx with a simple proxy to Gunicorn. Using ab, Gunicorn spits out 7700 requests/sec, where Nginx only does a 5000 request/sec. Is such a performance degradation expected? Hello world: #!/usr/bin/env python def application(environ, start_response): start_response("200 OK", [("Content-type", "text/plain")]) return [ "Hello World!" ] Gunicorn: gunicorn -w8 -k gevent --keep-alive 60 application:application Nginx (stripped): user www-data; worker_processes 4; pid /var/run/nginx.pid; events { worker_connections 768; } http { sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 65; types_hash_max_size 2048; upstream app_server { server 127.0.0.1:8000 fail_timeout=0; } server { listen 8080 default; keepalive_timeout 5; root /home/app/app/static; location / { proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; proxy_pass http://app_server; } } } Benchmark: (results: nginx TCP, nginx UNIX, gunicorn) ab -c 32 -n 12000 -k http://localhost:[8000|8080]/ Running gunicorn over a unix socket gives somewhat higher throughput (5500 r/s), but it still does't match raw gunicorn's performance.

  Read the article

• h264 inside FLV container vs. MP4 container?

  - by Gotys

  I am developing a tube site, and currently having issues with h264 format . By looking at youtube, I noticed they are putting their hi-def videos into mp4 container, so logically I did the same. Next, I installed mod_h264_streaming for lighttpd to make streaming and timeline-scrubbing work. Problem is, that large files (500mb+ at somewhat high resolution) take for EVER to even start buffering ( I read the flowplayer or other flash players need to download metadata first) . I moved the xmov atom to the front of the file with MP4Box (i tried qt-quickstart too) , and the problem didn't go away. Next I read online I need to interleave audio tracks, so I did that too. No change in slowness. So I tried putting the same exact h264 movie into an FLV container, and the playback buffering starts almost instantly - no slowness. So what am I missing here? Why would I choose MP4 container with mod_264_streaming module , which seems super-slow over a regular FLV container with lighttpd's built-in mod_flv_streaming ? Obviously many websites pick mp4 container , but I fail to understand why ? And as a side question - I tried using HTML5's VIDEO tag to try the same h264 MP4 movie, and the scrubbing is LIGHTING FAST! I looked into lighttpd's log file, and i noticed taht Flash Players append video.mp4?start=234 each time timeline is scrubbed, wheres HTML5's video tag does no such thing . Is this some sort of limitations of Flash ? Why Can't flash streaming be same fast as HTML5 streaming? Thanks to ALL who can help. I very much appreciate this community.

  Read the article

• Performance data collection for short-running, ephemeral servers

  - by ErikA

  We're building a medical image processing software stack, currently hosted on various AWS resources. As part of this application, we have a handful of long-running servers (database, load balancers, web application, etc.). Collecting performance data on those servers is quite simple - my go-to- recipe of Nagios (for monitoring/notifications) and Munin (for collection of performance data and displaying trends) will work just fine. However - as part of this application, we are constantly starting up and terminating compute instances on EC2. In typical usage, these compute instances start up, configure themselves, receive a job from a message queue, and then get to work processing that job, which takes anywhere from 15 minutes to over 8 hours. After job completion, these instances get terminated, never to be heard from again. What is a decent strategy for collecting performance data on these short-lived instances? I don't necessarily need monitoring on them - if they fail for whatever reason, our application will detect this and handle re-starting the job on another instance or raising the flag so an administrator can take a look at things. However, it still would be useful to collect information like CPU (user, idle, iowait, etc.), memory usage, network traffic, disk read/write data, etc. In our internal database, we track the instance ID of the machine that runs each job, and it would be quite helpful to be able to look up performance data for a specific instance ID for troubleshooting and profiling. Munin doesn't seem like a great candidate, as it requires maintaining a list of munin nodes in a text file - far from ideal for an environment with a high amount of churn, and for the short amount of time each node will be running, I'd rather keep the full-resolution data indefinitely than have RRD water down the data over time. In the end, my guess is that this will require a monitoring engine that: uses a database (MySQL, SQLite, etc.) for configuration and data storage exposes an API for adding/removing hosts and services Are there other things I should be thinking about when evaluating options? Perhaps I'm over-thinking this, though, and just ought to run sar at 1-minute intervals on these short-lived instances and collect the sar db files prior to termination.

  Read the article

• Mac Mavericks, ngircd localhost works, private IP doesn't

  - by user221945

  I have configured ngircd to listen on my private ip address. It doesn't. Localhost works fine. Configuration test: ngIRCd 21-IDENT+IPv6+IRCPLUS+SSL+SYSLOG+TCPWRAP+ZLIB-x86_64/apple/darwin13.2.0 Copyright (c)2001-2013 Alexander Barton () and Contributors. Homepage: http://ngircd.barton.de/ This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Reading configuration from "/opt/local/etc/ngircd.conf" ... OK, press enter to see a dump of your server configuration ... [GLOBAL] Name = irc.bellbookandpistol.com AdminInfo1 = Jaedreth AdminInfo2 = San Diego County CA, US AdminEMail = [email protected] HelpFile = /opt/local/share/doc/ngircd/Commands.txt Info = Server Info Text Listen = 10.0.1.5,127.0.0.1 MotdFile = MotdPhrase = "Welcome to irc.bellbookandpistol.com" Password = PidFile = Ports = 6667 ServerGID = wheel ServerUID = root [LIMITS] ConnectRetry = 60 IdleTimeout = 0 MaxConnections = 0 MaxConnectionsIP = 6 MaxJoins = -1 MaxNickLength = 9 MaxListSize = 0 PingTimeout = 120 PongTimeout = 20 [OPTIONS] AllowedChannelTypes = #&+ AllowRemoteOper = no ChrootDir = CloakHost = CloakHostModeX = CloakHostSalt = kBih5mu\kVI!DC6eifT(hd4m/0'zb/=: CloakUserToNick = no ConnectIPv4 = yes ConnectIPv6 = no DefaultUserModes = DNS = yes IncludeDir = /opt/local/etc/ngircd.conf.d MorePrivacy = no NoticeAuth = no OperCanUseMode = no OperChanPAutoOp = yes OperServerMode = no RequireAuthPing = no ScrubCTCP = no SyslogFacility = local5 WebircPassword = [SSL] CertFile = CipherList = HIGH:!aNULL:@STRENGTH DHFile = KeyFile = KeyFilePassword = Ports = [OPERATOR] Name = [REDACTED] Password = [REDACTED] Mask = [CHANNEL] Name = #BBP Modes = tnk Key = MaxUsers = 0 Topic = Welcome to the Bell, Book and Pistol IRC Server! KeyFile = As you can see, it should be listening on 10.0.1.5, but it isn't. After turning on Apache manually, port 80 works on 10.0.1.5, but port 6667 doesn't. It only works on localhost. Is there some terminal command I could use or some config file I could edit to get this to work?

  Read the article

• Is there a better way to do bonded vlan tagged interfaces with XEN

  - by AJ01

  We have a number of XEN servers all running CentOS or RHEL. The VM's that they run are all required to be on their own VLAN for no other reason than the customer expects them to be. Long story short however, I can't change this right now. We are also required to have bonding enabled on the interfaces. So to accommodat this we enslave eth1 and eth2 to bond0. We then create a seperate interface called bond0.VLANID where VLANID corresponds to the correct vlan; eg ifcfg-bond0.204 DEVICE=bond0.204 BOOTPROTO=static ONBOOT=yes VLAN=yes BRIDGE=xenvlan204 Bridge to XEN As you will see, we eventually have to bridge this out to XEN, and we do this by adding another interface called xenvlan204 (in this instance) which contains; ifcfg-xenvlan204 DEVICE=xenvlan204 BOOTPROTO=none ONBOOT=yes TYPE=bridge XEN Vm Config Finally in our XEN config for each VM, we add vif = [ "bridge=xenvlan204" ] This then allows the vm host to access that particular vlan The Problem We've noticed a few problems with this setup. One being that we currently create the interfaces manually. Which means if we add more vlan enabled interfaces and bridges we usually have to restart xend which is something I'm not so hot about. Also lower level staff have their heads melted by the number of interfaces and the risk of a mistake occurring is high. Secondly, it can take sometime for a host to come up if it has a number of vlan taged interfaces. Thirdly, its just not scaling well on the management aspects The Question Is there a better more flexible way to do this (in particular with Xen that ships with centos 5.3, 5.4 and 5.5 as we have to support all three) that leverages either scripting or other solutions to allow an arbitrary amount of interfaces to be created when a vm is instanced. Your advise and expertise is more that welcomed.

  Read the article

• Intermittent Trouble Entering Hibernate on WinXP

  - by kquinn

  My personal desktop, running 32-bit Windows XP SP2 (with 4GB RAM, 2.75GB addressable, swap disabled, hiberfil.sys existing and contiguous on C:\; SP3 is not installed because SP2 has been working fine and I do not want to re-qualify with SP3 just for sheer perversity) typically gets hibernated at night. For a long time this worked great, but recently the machine has had trouble entering hibernation. Sometimes when I press my power button (configured to hibernate), the box will start the procedure for hibernating (i.e., go to the blue "Windows XP" background logo and display a message about entering hibernation), but before displaying the usual blue-on-black hibernation progress bar it will drop back to the desktop. No error messages appear, on screen or in the system log. The only record of unsuccessful hibernation attempts in the system log, which proudly proclaims that "The Windows Image Acquisition (WIA) service entered the running state." once per failed hibernation attempt. The problem is almost certainly resource related: if I then close one or more applications which are running, and repeat the exact same process, the machine will hibernate perfectly. There does not appear to be a reliable high-water mark for virtual or physical memory use, below which the machine is guaranteed to hibernate; it's different every time (though typically, below about 1.1–1.4 GB memory usage seems to be where hibernate succeeds most often). Memory may not even be the relevant resource; as far as I know, it could also be handles or sockets. This behavior is relatively recent: it has only started in the last few months; before then, I could hibernate reliably no matter what the current resource use of the system. This machine claims to have hotfix Q909095 installed, but since the symptoms of my problem match KB909095 rather well, I'm suspicious if this fix is actually working as intended. Any ideas on how to fix this or where to start debugging?

  Read the article

• Simplest DNS solution for remote offices

  - by dunxd

  I look after a bunch of remote offices that connect via VPN - a Cisco ASA 5505 in each office acts as Firewall and VPN end point. Beyond that we keep things as simple as possible in the offices to minimise the support burden. We don't have any kind of server except in offices large enough to justify having someone dedicated to IT. Basically there is the ASA, some computers, a network printer and a switch. One of the problems I am seeing in a lot of offices is that DNS requests looking up hosts inside our network often fail - I'm assuming timeouts due to the offices internet connection (they are all in developing world countries) having some sub-optimal qualities (e.g. high latency caused by VSAT segments, or packet loss. The obvious solution to this is to have some sort of local DNS service that can serve local requests - so I think it would need to do zone transfers from our Microsoft Windows 2008 R2 DNS servers at HQ. However, simply installing Windows Servers in each office is both expensive, and creates a support burden. This got me thinking about pfsense/m0n0wall on embedded devices - those can act as a DNS server, and could be configured at HQ and sent out as just something that needs to be plugged into the network and can then be forgotten about by the staff locally. Maybe there are some alternatives to the ASA 5505 that include some DNS functionality. Has anyone here dealt with the problem, either using some kind of embedded device, or found some other solution? Any gotchas or reasons to avoid what I have suggested?

  Read the article

• Windows desktop virutalization instead of replacing work stations

  - by Chris Marisic

  I'm head of the IT department at the small business I work for, however I am primarily a software architect and all of my system administration experience and knowledge is ancillary to software development. At some point this year or next we will be looking at upgrading our workstation environment to a uniform Windows 7 / Office 2010 environment as opposed to the hodge podge collection of various OEM licensed editions of software that are on each different machine. It occurred to me that it is probably possible to forgo upgrading each workstation and instead have it be a dumb terminal to access a virutalization server and have their entire virtual workstation hosted on the server. Now I know basically anything is possible but is this a feasible solution for a small business (25-50 work stations)? Assuming that this is feasible, what type of rough guidelines exist for calculating the required server resources needed for this. How exactly do solutions handle a user accessing their VM, do they log on normally to their physical workstation and then use remote desktop to access their VM, or is it usually done with a client piece of software to negotiate this? What types of software available for administering and monitoring these VM's, can this functionality be achieved out of box with Microsoft Server 2008? I'm mostly interested in these questions relating to Server 2008 with Hyper-V but fell free to offer insight with VMware's product line up, especially if there's any compelling reasons to choose them over Hyper-V in a Microsoft shop. Edit: Just to add some more information on implementation goals would be to upgrade our platform from a Win2k3 / XP environment to a full Windows 2008 / Win7 platform without having to perform any of that associated work with our each differently configured workstation. Also could anyone offer any realistic guidelines for how big of hardware is needed to support 25-50 workstations virtually? The majority the workstations do nothing except Office, Outlook and web. The only high demand workstations are the development workstations which would keep everything local.

  Read the article

• Java: very slow tomcat and too big war file

  - by NaN

  I created some sort of RESTful API backend for a mobile app. It's written completely in Java using Jersey as Framework. At the moment no database is used, it's all in the memory, but this is no problem so far (it's only for prototyping purposes). I ordered the smallest package from digital ocean and installed tomcat7. All in all tomcat works, but I have three major problems: 1) It takes a long time until tomcat deploys the app: I deploy it per tomcat manager and it takes about 2 minutes unit the site works (excl. war upload time). 2) The war files are quite big (16MB): I don't know why they are so big. There are no database dependencies and most logic is written in plain java. Okay, we are using jersey, but 16MB are a lot for the logic of a small webservice. 3) I have to restart tomcat all 3 days or so. It looks like a memory leak or something similar. If the app runs for a few days the response time is quite high and the server seems to be frozen. It works again, if I restart tomcat per ssh. You can find my mvn pom file right here. Do you have some tips? Are there good tomcat alternatives?

  Read the article

< Previous Page | 497 498 499 500 501 502 503 504 505 506 507 508  | Next Page >