[TriLUG] Ubuntu FakeRAID or Software

[Brian McCullough]

On Thu, Nov 04, 2010 at 02:13:35PM -0400, matt at noway2.thruhere.net wrote:
> 
> Regarding the time I had trouble (From Steve Pinkham's question:
> 
> "Did you let MD sync first? if not, then yes, you would definately cause
> corruption this way. "cat /proc/mdstat" to make sure all disks are
> synced before pulling one ;-)"
> 
> I am pretty sure the drives were synced, but I suspect I needed to command
> mdadm to remove the device from the array before I powered down. I suspect
> that by just shutting down and removing the device that it came up in an
> unexpectedly degraded state, rather than a sane one.
> 
> So Brian, if you are ever think of testing it in this fashion, be sure to
> use the mdadm commands to remove the device first.


Different Brian ---

But the point if this test is to see what happens if a drive fails, and it rarely does so in a well-ordered way.

Pulling the power, or in some other way removing it unexpectedly is a good test for a RAID subsystem.


I have also been running Linux Software RAID ( usually RAID 1 ) for quite a few years on various machines with no issues.  I have also tried, occasionally, the idea or putting / on RAID, but never /boot. ( that was before GRUB knew how to find /boot somewhere other than a standard ATA drive. )


Brian