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  • Introduction to WebCenter Personalization: &ldquo;The Conductor&rdquo;

    - by Steve Pepper
    There are some new faces in the town of WebCenter with the latest 11g PS3 release.  A new component has introduced itself as "Oracle WebCenter Personalization", a.k.a WCP, to simplify delivery of a personalized experience and content to end users.  This posting reviews one of the primary components within WCP: "The Conductor". The Conductor: This ain't just an ordinary cloud... One of the founding principals behind WebCenter Personalization was to provide an open client-side API that remains independent of the technology invoking it, in addition to independence from the architecture running it.  The Conductor delivers this, and much, much more. The Conductor is the engine behind WebCenter Personalization that allows flow-based documents, called "Scenarios", to be managed and executed on the server-side through a well published and RESTful api.      The Conductor also supports an extensible model for custom provider integration that can be easily invoked within a Scenario to promote seamless integration with existing business assets. Introducing the Scenario Conductor Scenarios are declarative offline-authored documents using the custom Personalization JDeveloper bundle included with WebCenter.  A Scenario contains one (or more) statements that can: Create variables that are scoped to the current execution context Iterate over collections, or loop until a specific condition is met Execute one or more statements when a condition is met Invoke other scenarios that exist within the same namespace Invoke a data provider that integrates with custom applications Once a variable is assigned within the Scenario's execution context, it can be referenced anywhere within the same Scenario using the common Expression Language syntax used in J2EE web containers. Scenarios are then published and tested to the Integrated WebLogic Server domain, or published remotely to other domains running WebCenter Personalization. Various Client-side Models The Conductor server API is built upon RESTful services that support a wide variety of clients able to communicate over HTTP.  The Conductor supports the following client-side models: REST:  Popular browser-based languages can be used to manage and execute Conductor Scenarios.  There are other public methods to retrieve configured provider metadata that can be used by custom applications. The Conductor currently supports XML and JSON for it's API syntax. Java: WebCenter Personalization delivers a robust and light-weight java client with the popular Jersey framework as it's foundation.  It has never been easier to write a remote java client to manage remote RESTful services. Expression Language (EL): Allow the results of Scenario execution to control your user interface or embed personalized content using the session-scoped managed bean.  The EL client can also be used in straight JSP pages with minimal configuration. Extensible Provider Framework The Conductor supports a pluggable provider framework for integrating custom code with Scenario execution.  There are two types of providers supported by the Conductor: Function Provider: Function Providers are simple java annotated classes with static methods that are meant to be served as utilities.  Some common uses would include: object creation or instantiation, data transformation, and the like.  Function Providers can be invoked using the common EL syntax from variable assignments, conditions, and loops. For example:  ${myUtilityClass:doStuff(arg1,arg2))} If you are familiar with EL Functions, Function Providers are based on the same concept. Data Provider: Like Function Providers, Data Providers are annotated java classes, but they must adhere to a much more strict object model.  Data Providers have access to a wealth of Conductor services, such as: Access to namespace-scoped configuration API that can be managed by Oracle Enterprise Manager, Scenario execution context for expression resolution, and more.  Oracle ships with three out-of-the-box data providers that supports integration with: Standardized Content Servers(CMIS),  Federated Profile Properties through the Properties Service, and WebCenter Activity Graph. Useful References If you are looking to immediately get started writing your own application using WebCenter Personalization Services, you will find the following references helpful in getting you on your way: Personalizing WebCenter Applications Authoring Personalized Scenarios in JDeveloper Using Personalization APIs Externally Implementing and Calling Function Providers Implementing and Calling Data Providers

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  • Dealing with Fine-Grained Cache Entries in Coherence

    - by jpurdy
    On occasion we have seen significant memory overhead when using very small cache entries. Consider the case where there is a small key (say a synthetic key stored in a long) and a small value (perhaps a number or short string). With most backing maps, each cache entry will require an instance of Map.Entry, and in the case of a LocalCache backing map (used for expiry and eviction), there is additional metadata stored (such as last access time). Given the size of this data (usually a few dozen bytes) and the granularity of Java memory allocation (often a minimum of 32 bytes per object, depending on the specific JVM implementation), it is easily possible to end up with the case where the cache entry appears to be a couple dozen bytes but ends up occupying several hundred bytes of actual heap, resulting in anywhere from a 5x to 10x increase in stated memory requirements. In most cases, this increase applies to only a few small NamedCaches, and is inconsequential -- but in some cases it might apply to one or more very large NamedCaches, in which case it may dominate memory sizing calculations. Ultimately, the requirement is to avoid the per-entry overhead, which can be done either at the application level by grouping multiple logical entries into single cache entries, or at the backing map level, again by combining multiple entries into a smaller number of larger heap objects. At the application level, it may be possible to combine objects based on parent-child or sibling relationships (basically the same requirements that would apply to using partition affinity). If there is no natural relationship, it may still be possible to combine objects, effectively using a Coherence NamedCache as a "map of maps". This forces the application to first find a collection of objects (by performing a partial hash) and then to look within that collection for the desired object. This is most naturally implemented as a collection of entry processors to avoid pulling unnecessary data back to the client (and also to encapsulate that logic within a service layer). At the backing map level, the NIO storage option keeps keys on heap, and so has limited benefit for this situation. The Elastic Data features of Coherence naturally combine entries into larger heap objects, with the caveat that only data -- and not indexes -- can be stored in Elastic Data.

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  • How to "paint" the data layer of a CD using a CD drive?

    - by Jens
    I am looking for software to "paint" geometric shapes, dots or lines on the data layer of a writable CD (or DVD) using a standard drive. These do not have to be visible to the naked eye; I'd try to abuse the small dot size on the CD for some scientific measurements. I am aware of the "LightScribe" feature of some drives and that is not what I am looking for. Most of the software available is of course limited to write music or data, on does not offer the low-level "place a dot at this radius, this angle"-functionality. Is there something out there for me?

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  • When things go awry

    - by Phil Factor
    The moment the Entrepreneur opened his mouth on prime-time national TV, spelled out the URL and waxed big on how exciting ‘his’ new website was, I knew I was in for a busy night. I’d designed and built it. All at once, half a million people tried to log into the website. Although all my stress-testing paid off, I have to admit that the network locked up tight long before there was any danger of a database or website problem. Soon afterwards, the Entrepreneur and the Big Boss were there in the autopsy meeting. We picked through all our systems in detail to see how they’d borne the unexpected strain. Mercifully, in view of the sour mood of the Big Boss, it turned out that the only thing we could have done better was buy a bigger pipe to and from the internet. We’d specified that ‘big pipe’ when designing the system. The Big Boss had then railed at the cost and so we’d subsequently compromised. I felt that my design decisions were vindicated. The Big Boss brooded for a while. Then he made the significant comment: “What really ****** me off is the fact that, for ten minutes, we couldn’t take people’s money.” At that point I stopped feeling smug. Had the internet connection been better, the system would have reached its limit and failed rather precipitously, and that wasn’t what he wanted. Then it occurred to me that what had gummed up the connection was all those images on the site, that had made it so impressive for the visitors. If there had been a way to automatically pare down the site to the bare essentials under stress… Hmm. I began to consider disaster-recovery in the broadest sense – maintaining a service in spite of unusual or unexpected events. What he said makes a lot of sense: sacrifice whatever isn’t essential to keep the core service running when we approach the capacity limits. Maybe in IT we should borrow (or revive) the business concept of the ‘Skeleton service’, maintaining only the priority parts under stress, using a process that is well-prepared and carefully rehearsed. How might this work? Whatever the event we have to prepare for, it is all about understanding the priorities; knowing what one can dispense with when the going gets tough. In the event of database disaster, it’s much faster to deploy a skeletal system with only the essential data than to restore the entire system, though there would have to be a reconciliation process to update the revived database retrospectively, once the emergency was over. It isn’t just the database that could be designed for resilience. One could prepare for unusually high traffic in a website by designing a system that degraded gradually to a ‘skeletal’ site, one that maintained the commercial essentials without fat images, JavaScript libraries and razzmatazz. This is all what the Big Boss scathingly called ‘a mere technicality’. It seems to me that what is needed first is a culture of application and database design which acknowledges that we live in a very imperfect world, and react accordingly when things go awry.

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  • The Problem Should Define the Process, Not the Tool

    - by thatjeffsmith
    All around awesome tool, but not the only gadget in your toolbox.I’m stepping down from my SQL Developer pulpit today and standing up on my philosophical soap box. I’m frequently asked to help folks transition from one set of database tools over to Oracle SQL Developer, which I’m MORE than happy to do. But, I’m not looking to simply change the way people interact with Oracle database. What I care about is your productivity. Is there a faster, more efficient way for you to connect the dots, get from A to B, or just get home to your kids or to the pub for happy hour? If you have defined a business process around a specific tool, what happens when that tool ‘goes away?’ Does the business stop? No, you feel immediate pain until you are able to re-implement the process using another mechanism. Where I get confused, or even frustrated, is when someone asks me to redesign our tool to match their problem. Tools are just tools. Saying you ‘can’t load your data anymore because XYZ’ isn’t valid when you could easily do that same task via SQL*Loader, Create Table As Selects, or 9 other different mechanisms. Sometimes changes brings opportunity for improvement in the process. Don’t be afraid to step back and re-evaluate a problem with a fresh set of eyes. Just trying to replicate your process in another tool exactly as it was done in the ‘old tool’ doesn’t always make sense. Quick sidebar: scheduling a Windows program to kick off thousands if not millions of table inserts from Excel versus using a ‘proper’ server process using SQL*Loader and or external tables means sacrificing scalability and reliability for convenience. Don’t let old habits blind you to new solutions and possibilities. Of couse I’m not going to sit here and say that our tools aren’t deficient in some areas or can’t be improved upon. But I bet if we work together we can find something that’s not only better for the business, but is also better for you. What do you ‘miss’ since you’ve started using SQL Developer as your primary Oracle database tools? I’d love to start a thread here and share ideas on how we can better serve you and your organizations needs. The end solution might not look exactly what you have in mind starting out, but I had no idea I’d be a Product Manager when I started college either What can you no longer ‘do’ since you picked up SQL Developer? What hurts more than it should? What keeps you from being great versus just good?

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  • Upload Recordings Of The Problem To Your SR

    - by jhpierce
    Do you find yourself trying several times to explain a problem in a Service Request? Does the support engineer ask more than once for clarification? If so, you might be interested in DITO -- Demo It To Oracle. DITO uses CamStudio (free download!) to record the exact nature of the problem, and upload the output to your SR. The following articles provide more details: Working with Support - MOSSOS (Doc ID 1265130.1) "Demo It To Oracle" (DITO) - CamStudio Help ( Doc ID 11.1) Why take up valuable time first explaining the problem, then trying to get a web conference setup to show exactly what is going on? The next time you file an SR, try including a recording showing exactly which application is failing, where it is failing, and what it looks like when it fails.

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  • A way to store potentially infinite 2D map data?

    - by Blam
    I have a 2D platformer that currently can handle chunks with 100 by 100 tiles, with the chunk coordinates are stored as longs, so this is the only limit of maps (maxlong*maxlong). All entity positions etc etc are chunk relevant and so there is no limit there. The problem I'm having is how to store and access these chunks without having thousands of files. Any ideas for a preferably quick & low HD cost archive format that doesn't need to open everything at once?

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  • Multiple vulnerabilities in ImageMagick

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2004-0981 Buffer overflow vulnerability 10.0 ImageMagick Solaris 10 SPARC: 136882-03 X86: 136883-03 CVE-2005-0397 Format string vulnerability 7.5 CVE-2005-0759 Denial of service (DoS) vulnerability 5.0 CVE-2005-0760 Denial of service (DoS) vulnerability 5.0 CVE-2005-0761 Denial of service (DoS) vulnerability 5.0 CVE-2005-0762 Buffer overflow vulnerability 7.5 CVE-2005-1739 Denial of service (DoS) vulnerability 5.0 CVE-2007-4985 Denial of service (DoS) vulnerability 4.3 CVE-2007-4986 Numeric Errors vulnerability 6.8 CVE-2007-4987 Numeric Errors vulnerability 9.3 CVE-2007-4988 Numeric Errors vulnerability 6.8 This notification describes vulnerabilities fixed in third-party components that are included in Sun's product distribution.Information about vulnerabilities affecting Oracle Sun products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • The Role of High Availability Computing on Business Continuity -- Part 1 of 2

    For organizations that can't afford, sustain or justify downtime -- developing, implementing and testing a high-availability computing strategy is essential. Unplanned downtime affects company reputation, stock price and competitive strategy. It can even delay IT innovation projects necessary for delivering new services to customers. LLearn how Oracle's approach to high availability computing is fundamentally different from the traditional model. Hear Oracle Thought Leader Balaji Bashyam (Vice President, Global Database Support) discuss high availability strategy, best practices, and the effects of availability on business, in a question and answer interview format. This podcast is presented in two parts and is intended for an audience of decision makers and influencers. Part 1 of 2

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  • Upload Recordings Of The Problem To Your SR

    - by Irina
    Do you find yourself trying several times to explain a problem in a Service Request? Does the support engineer ask more than once for clarification? If so, you might be interested in DITO -- Demo It To Oracle. DITO uses CamStudio (free download!) to record the exact nature of the problem, and upload the output to your SR. The following articles provide more details: Working with Support - MOSSOS (Doc ID 1265130.1) "Demo It To Oracle" (DITO) - CamStudio Help ( Doc ID 11.1) Why take up valuable time first explaining the problem, then trying to get a web conference setup to show exactly what is going on? The next time you file an SR, try including a recording showing exactly which application is failing, where it is failing, and what it looks like when it fails.

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  • Can You Get Recovered Data From Wet Hard Drives?

    Most of us are aware of the fact that it is not recommended to have water and your hard drive connect with each other. The protective hard casing of your hard drive is not designed to withstand conta... [Author: Michiel Van Kets - Computers and Internet - May 08, 2010]

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  • How to avoid oscillation by async event based systems?

    - by inf3rno
    Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and hubs. Data sources are publishing and subscribing for events and hubs are relaying events to data sources. By handling an event a data source will change it state described in the event. By publishing an event the data source puts its current state to the event, so other data sources can use that information to change their state accordingly. The only problem with this system, that events can be reflected from the hub or from the other data sources, and that can put the system into an infinite oscillation (by async or infinite loop by sync). For example A -- data source B -- data source H -- hub A -> H -> A -- reflection from the hub A -> H -> B -> H -> A -- reflection from another data source By sync it is relatively easy to solve this issue. You can compare the current state with the event, and if they are equal, you don't change the state and raise the same event again. By async I could not find a solution yet. The state comparison does not work by async event handling because there is eventual consistency, and new events can be published in an inconsistent state causing the same oscillation. For example: A(*->x) -> H -> B(y->x) -- can go parallel with B(*->y) -> H -> A(x->y) -- so first A changes to x state while B changes to y state -- then B changes to x state while A changes to y state -- and so on for eternity... What do you think is there an algorithm to solve this problem? If there is a solution, is it possible to extend it to prevent oscillation caused by multiple hubs, multiple different events, etc... ? update: I don't think I can make this work without a lot of effort. I think this problem is just the same as we have by syncing multiple databases in a distributed system. So I think what I really need is constraints if I want to prevent this problem in an automatic way. What constraints do you suggest?

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  • Multiple vulnerabilities in Firefox web browser

    - by chandan
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2011-3062 Numeric Errors vulnerability 6.8 Firefox web browser Solaris 11 11/11 SRU 9.5 Solaris 10 SPARC: 145080-11 X86: 145081-10 CVE-2012-0467 Denial of service (DoS) vulnerability 10.0 CVE-2012-0468 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 10.0 CVE-2012-0469 Resource Management Errors vulnerability 10.0 CVE-2012-0470 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 10.0 CVE-2012-0471 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability 4.3 CVE-2012-0473 Numeric Errors vulnerability 5.0 CVE-2012-0474 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability 4.3 CVE-2012-0477 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability 4.3 CVE-2012-0478 Permissions, Privileges, and Access Controls vulnerability 9.3 CVE-2012-0479 Identity spoofing vulnerability 4.3 This notification describes vulnerabilities fixed in third-party components that are included in Sun's product distribution.Information about vulnerabilities affecting Oracle Sun products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • Google Analytics Not tracking data correctly IP-address issue?

    - by PaperThick
    I have developed a small site for a client and the site has been placed inside a <iframe> at the clients site. The GA-script I'm using looks like this: <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push( ['_setAccount', 'UA-XXXXXXXX-2'], //My company's GA-account ['_trackPageview'], ['b._setAccount', 'UA-XXXXXXXX-1'], // Test GA-account ['b._trackPageview'], ['th._setAccount', 'UA-XXXXXXX-3'], ['th._setDomainName', '.clientdomain.se'], // Client GA-account ['th._trackPageview'] ); (function () { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> </head> As you can see I report the GA pageviews to the client as well. The GA script is tracking visitors and pageviews at both ends. But the problem is that on my clients side the visitor-count is more than double what they are on my end (20 000 vs 5 000). At first I thought that it was being duplicated at some point but when I checked my Crazy-Egg account I saw that it had tracked over 10 000 visits and then stopped tracking because that was my limit on the account. The page my site is on is on a IP-address (http://XXX.XXX.XX.X/campaign/) and not on a "valid url". Could that be an issue why some of the visitors isn't beeing tracked? Thanks in advance

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  • For an ORM supporting data validation, should constraints be enforced in the database as well?

    - by Ramnique Singh
    I have always applied constraints at the database level in addition to my (ActiveRecord) models. But I've been wondering if this is really required? A little background I recently had to unit test a basic automated timestamp generation method for a model. Normally, the test would create an instance of the model and save it without validation. But there are other required fields that aren't nullable at the in the table definition, meaning I cant save the instance even if I skip the ActiveRecord validation. So I'm thinking if I should remove such constraints from the db itself, and let the ORM handle them? Possible advantages if I skip constraints in db, imo - Can modify a validation rule in the model, without having to migrate the database. Can skip validation in testing. Possible disadvantage? If its possible that ORM validation fails or is bypassed, howsoever, the database does not check for constraints. What do you think? EDIT In this case, I'm using the Yii Framework, which generates the model from the database, hence database rules are generated also (though I could always write them post-generation myself too).

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  • Correct permissions for /var/www and wordpress

    - by dpbklyn
    Hello and thank you in advance! I am relatively new to ubuntu, so please excuse the newbie-ness of this question... I have set up a LAMP server (ubuntu server 11.10) and I have access via SSH and to the "it works" page from a web browser from inside my network (via ip address) and from outside using dyndns. I have a couple of projects in development with some outside developers and I want to use this server as a development server for testing and for client approvals. We have some Wordpress projects that sit in subdirectories in /var/www/wordpress1 /var/www/wordpress2, etc. I cannot access these sub directories from a browser in order to set up WP--or (I assume) to see the content on a browser. I get a 403 Forbidden error on my browser. I assume that this is a permissions problem. Can you please tell me the proper settings for the permissions to: 1) Allow the developers and me to read/write. 2) to allow WP set up and do its thing 3) Allow visitors to access the site(s) via the web. I should also mention that the subfolder are actually simlinks to folder on another internal hdd--I don't think this will make a difference, but I thought I should disclose. Since I am a newbie to ubuntu, step-by-step directions are greatly appreciated! Thank you for taking the time! dp total 12 drwxr-xr-x 2 root root 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 root root 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 root root 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 root root 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 root root 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress Here is the result of using chown -R www-data:www-data /var/www total 12 drwxr-xr-x 2 www-data www-data 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 www-data www-data 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 www-data www-data 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 www-data www-data 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 www-data www-data 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress I am still unable to access via browser...

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  • Are We Losing a Standard (Edition) Data Recovery Technology?

    - by AllenMWhite
    One of the coolest technologies Microsoft released with SQL Server 2005 was Database Mirroring, which provided the ability to have a failover copy of a database on another SQL Server instance, and have the ability to automatically failover to that copy should a problem occur with the primary database. What was even cooler was that this new technology was available on Standard Edition! Mom and Pop shops could afford to implement a high availability solution without paying an extra tens of thousands...(read more)

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  • How to apply Data Oriented Design with Object Oriented Programming?

    - by Pombal
    Hi. I've read lots of articles about DOD and I understand it but I can't design an Object Oriented system with DOD in mind, I think my OOP education is blocking me. How should I think to mix the two? The objective is to have a nice OO interface while using DOD behind the scenes. I saw this too but didn't help much: http://stackoverflow.com/questions/3872354/how-to-apply-dop-and-keep-a-nice-user-interface

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  • Bunny Inc. Season 2: Find Specialist Partner Resources for Success

    - by kellsey.ruppel
    You may need an additional hand to improve your IT infrastructure, or advice to evolve existing enterprise applications. Or perhaps you’re seeking revolutionary ideas to refresh online presence. Whatever the case, spotting the right partners’ ecosystem will be a central step to grow your business. Don't be a Hare Inc. company by wasting valuable time sourcing relevant expertise, competencies and proven successes on Oracle's product portfolio on your own. Follow Bunny Inc. in the fourth episode of the saga and discover what our worldwide partner community can do for you thanks to the new Oracle Partner Network Specialized program. 

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  • How can I locate the frames of a spritesheet PNG based on this PLIST data?

    - by kitsune
    Someone asked me to reskin a certain game. Now he only sent me the whole sprite PNG and PLIST files of the sprites. He instructed me to rename each sprite with the same name corresponding to each original sprite. The problem is, he gave me the whole sprite sheet instead of each individual sprite and the PLIST. Now yes, I can read the PNG filenames from the PLIST, but I cannot rename the reskin sprites I did because I'm not sure which sprite is boy_gun_3_3.png; there are multiple guns, I don't know which is which. Is there a way to extract individual accurately named individual PNG files from the single sprite sheet using the PLIST?

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  • Deduping your redundancies

    - by nospam(at)example.com (Joerg Moellenkamp)
    Robin Harris of Storagemojo pointed to an interesting article about about deduplication and it's impact to the resiliency of your data against data corruption on ACM Queue. The problem in short: A considerable number of filesystems store important metadata at multiple locations. For example the ZFS rootblock is copied to three locations. Other filesystems have similar provisions to protect their metadata. However you can easily proof, that the rootblock pointer in the uberblock of ZFS for example is pointing to blocks with absolutely equal content in all three locatition (with zdb -uu and zdb -r). It has to be that way, because they are protected by the same checksum. A number of devices offer block level dedup, either as an option or as part of their inner workings. However when you store three identical blocks on them and the devices does block level dedup internally, the device may just deduplicated your redundant metadata to a block stored just once that is stored on the non-voilatile storage. When this block is corrupted, you have essentially three corrupted copies. Three hit with one bullet. This is indeed an interesting problem: A device doing deduplication doesn't know if a block is important or just a datablock. This is the reason why I like deduplication like it's done in ZFS. It's an integrated part and so important parts don't get deduplicated away. A disk accessed by a block level interface doesn't know anything about the importance of a block. A metadata block is nothing different to it's inner mechanism than a normal data block because there is no way to tell that this is important and that those redundancies aren't allowed to fall prey to some clever deduplication mechanism. Robin talks about this in regard of the Sandforce disk controllers who use a kind of dedup to reduce some of the nasty effects of writing data to flash, but the problem is much broader. However this is relevant whenever you are using a device with block level deduplication. It's just the point that you have to activate it for most implementation by command, whereas certain devices do this by default or by design and you don't know about it. However I'm not perfectly sure about that ? given that storage administration and server administration are often different groups with different business objectives I would ask your storage guys if they have activated dedup without telling somebody elase on their boxes in order to speak less often with the storage sales rep. The problem is even more interesting with ZFS. You may use ditto blocks to protect important data to store multiple copies of data in the pool to increase redundancy, even when your pool just consists out of one disk or just a striped set of disk. However when your device is doing dedup internally it may remove your redundancy before it hits the nonvolatile storage. You've won nothing. Just spend your disk quota on the the LUNs in the SAN and you make your disk admin happy because of the good dedup ratio However you can just fall in this specific "deduped ditto block"trap when your pool just consists out of a single device, because ZFS writes ditto blocks on different disks, when there is more than just one disk. Yet another reason why you should spend some extra-thought when putting your zpool on a single LUN, especially when the LUN is sliced and dices out of a large heap of storage devices by a storage controller. However I have one problem with the articles and their specific mention of ZFS: You can just hit by this problem when you are using the deduplicating device for the pool. However in the specifically mentioned case of SSD this isn't the usecase. Most implementations of SSD in conjunction with ZFS are hybrid storage pools and so rotating rust disk is used as pool and SSD are used as L2ARC/sZIL. And there it simply doesn't matter: When you really have to resort to the sZIL (your system went down, it doesn't matter of one block or several blocks are corrupt, you have to fail back to the last known good transaction group the device. On the other side, when a block in L2ARC is corrupt, you simply read it from the pool and in HSP implementations this is the already mentioned rust. In conjunction with ZFS this is more interesting when using a storage array, that is capable to do dedup and where you use LUNs for your pool. However as mentioned before, on those devices it's a user made decision to do so, and so it's less probable that you deduplicating your redundancies. Other filesystems lacking acapability similar to hybrid storage pools are more "haunted" by this problem of SSD using dedup-like mechanisms internally, because those filesystem really store the data on the the SSD instead of using it just as accelerating devices. However at the end Robin is correct: It's jet another point why protecting your data by creating redundancies by dispersing it several disks (by mirror or parity RAIDs) is really important. No dedup mechanism inside a device can dedup away your redundancy when you write it to a totally different and indepenent device.

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  • would it be bad to put <span> tags within the <head>, for grouping meta data in schema.org format?

    - by hdavis84
    Alright, I'm currently practicing schema.org microdata, and trying to find the best route for every site I build. I have found that i can piggyback itemprops on open graph meta tags. I would like to piggyback more itemprops on opengraph meta tags. However, schema.org requires you to change itemtypes to define all aspects of a "thing". Say I'm defining a LocalBusiness. Open graph has street address, locality, and region i'd like to piggyback on. I'd have to do something like: <html lang="en" itemscope itemtype="http://schema.org/LocalBusiness"> <head> ... <meta itemprop="name" content="Business Name" /> <meta property="og:url" itemprop="url" content="http://example.com" /> <meta property="og:image" itemprop="image" content="http://example.com/logo.png" /> <span itemprop="address" itemscope itemtype="http://schema.org/PostalAddress"> <meta property="og:street-address" itemprop="streetAddress" content="1234 Amazing Rd." /> <meta property="og:locality" itemprop="addressLocality" content="Greenfield" /> <meta property="og:region" itemprop="addressRegion" content="IN" /> </span> </head> Although there's more that can be added in, this is enough of an example to show what I'm trying to achieve. I've searched the web to see if it is an issue to use spans in the head or not, because I don't want invalid markup. I know I can mark up the address information in the body of the pages, but the route above would be more efficient. Does anyone have an answer for this?

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  • The Convergence of Risk and Performance Management

    Historically, the market has viewed Enterprise Performance Management (EPM) and Governance, Risk and Compliance (GRC) as separate processes and solutions. But these two worlds are coming together-in fact industry analyst firms such as AMR Research believe that by the end of 2009, risk management will be part of every EPM discussion. Tune into this conversation with John O'Rourke, VP of Product Marketing for Oracle Enterprise Performance Management Solutions, and Karen dela Torre, Senior Director of Product Marketing for Financial Applications to learn how EPM and GRC are converging, what the integration points are, and what Oracle is doing to help customers perform more effective risk and performance management.

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