I took over a fairly simple server setup with the following RAID 1 config running Ubuntu 11.10 (Kernel 3.0.0-12-server x86_64):

=> ctrl all show config

Smart Array P410i in Slot 0 (Embedded)    (sn: removed)

   array A (SAS, Unused Space: 1335535 MB)


      logicaldrive 1 (279.4 GB, RAID 1, OK)

      physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 1 TB, OK)
      physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 1 TB, OK)

Initially there were two 300GB disks that got replaced by 1TB disks and I now have to extend the logical volume to use that extra space.

However, when trying to do so I get the following warning:

=> ctrl slot=0 ld 1 modify size=max

Warning: Extension may not be supported on certain operating systems.
         Performing extension on these operating systems can cause data to
         become inaccessible. See ACU documentation for details. Continue?
         (y/n)

Is it safe to say yes or am I at risk of corrupting the file system / loosing data? Rearranging and extending the file system afterwards shouldn't be an issue as I can take the server offline and boot from a gparted live disk.

Here's the config of the RAID controller in use:

=> ctrl all show detail

Smart Array P410i in Slot 0 (Embedded)
   Bus Interface: PCI
   Slot: 0
   Serial Number: removed
   RAID 6 (ADG) Status: Disabled
   Controller Status: OK
   Hardware Revision: Rev C
   Firmware Version: 5.12
   Rebuild Priority: Medium
   Expand Priority: Medium
   Surface Scan Delay: 15 secs
   Surface Scan Mode: Idle
   Wait for Cache Room: Disabled
   Surface Analysis Inconsistency Notification: Disabled
   Post Prompt Timeout: 0 secs
   Cache Board Present: False
   Drive Write Cache: Disabled
   SATA NCQ Supported: True

And the partition table:

Number  Start   End    Size    Type      File system     Flags
 1      1049kB  274GB  274GB   primary   ext4            boot
 2      274GB   300GB  25.8GB  extended
 5      274GB   300GB  25.8GB  logical   linux-swap(v1)