On 4/9/11 10:39 PM, Jeffrey J. Kosowsky wrote:
> Les Mikesell wrote at about 11:31:28 -0500 on Saturday, April 9, 2011:
> > On 4/9/11 12:28 AM, Saturn2888 wrote:
> > > :: mdadm ::
> > This is what I use, with a raid1 created with 3 members but one missing.
> I
> > periodically rotate disks into a hotswap sata bay, add it long enough to
> > re-sync, and then fail and remove it to take offsite. The sync
> > operation do
>
> I tried this just *once* and ended up losing 2 years of backups!
> Specifically, I had been running software RAID1 on 2 1TB disks for 2
> years without any problems. Then on Black Friday, I bought a new 1TB
> disk and had the brilliant idea of adding it temporarily to my RAID
> array to create a backup. I mounted it via an external USB
> enclosure. Well, somehow it crashed during rebuilding, leaving the new
> 3rd disk unreadable and corrupting the pool on the original disk --
> specifically, a number of pool files and directories were deleted or
> became unreadable. Not sure how and/or why this happened, but the
> LESSON is that RAID is not perfect and it can corrupt everything. If I
> do this again in the future, I probably should at a minimum remove one
> of the internal drives to use as backup later on in case something
> happens. Alternatively, I probably would have been better just taking
> BackupPC offline and doing a 'dd' to the new disk
I've never heard of raid sync affecting the original disk(s). I've been doing
it for years, first with a set of firewire external drives (which also had USB
but it was slower), then the sata bays. There might be problems in adding more
members than originally created in the set, though. In your situation I would
have failed/removed one of the internal members with mdadm, then added the usb
in its place. With my rotation, I make it a point to never have all the disks
in one place or connected at the same time, so even if something did wipe all
three connected disks, I'd be able to recover back to the last swap from the
offsite copy. When I first started, I only used 1 permanent disk, but had a
hardware problem with it mid-sync which, like your experience left both copies
unusable. After that I started using a 3-member raid1 with two always present
and the 3rd only connected long enough to sync.
--
Les Mikesell
lesmikesell AT gmail DOT com
------------------------------------------------------------------------------
Xperia(TM) PLAY
It's a major breakthrough. An authentic gaming
smartphone on the nation's most reliable network.
And it wants your games.
http://p.sf.net/sfu/verizon-sfdev
_______________________________________________
BackupPC-users mailing list
BackupPC-users AT lists.sourceforge DOT net
List: https://lists.sourceforge.net/lists/listinfo/backuppc-users
Wiki: http://backuppc.wiki.sourceforge.net
Project: http://backuppc.sourceforge.net/
|
