Kernel Modules in Fedora -x

Les Mikesell lesmikesell at gmail.com
Wed Aug 8 16:04:25 UTC 2007


Jarod Wilson wrote:

>> The place I want it is as a 3rd member of a RAID1 set that is used for
>> the pooled file storage for backuppc - which hardlinks all identical
>> files it finds across your backup set.  This is extremely busy during
>> backups and takes an impractically long time to copy with tar or other
>> file-oriented means because of the way hardlinks are re-constructed
>> (many days for a 250 gig drive), while a raid-sync will complete in a
>> couple of hours.  There's probably a better way to do that now with LVM
>> snapshots but that's getting off the topic of reliability.
> 
> Wait... So you're essentially creating a cloned volume on the firewire
> disk via a raid resync, rather than having the initial backup written
> with the firewire disk connected in the raid set? If so, that's
> moderately amusing... :)

The object is to make copies that can be rotated offsite weekly and 
that's the first way I found that actually worked.  In earlier attempts 
I tried to use one internal, one external drive as a mirrored set, just 
failing/removing the external drive and adding a different one 
periodically.  That didn't work well because the drive would frequently 
be marked as failed even though it really didn't have a problem, and on 
any reboot it would have to be re-synced manually.  Also while trying to 
do it this way I had an actual failure on the internal drive which took 
some contortions to recover.  So, I created a 3-member raid1 with one 
device specified as "missing" and now have 2 internal drives that run 
mirrored all the time and at weekly intervals add the external drive and 
wait for the sync.  Then I momentarily stop the backuppc service, 
unmount the drive, fail the device in the raid, and remove it. I can 
then access the external drive with a laptop and could do disaster 
recovery restores without any other special equipment. Backuppc's 
compression/pooling scheme crams about 700gigs worth of archives on the 
250 gig disks that I am using and it beats trying to find things on 
tapes.  But, for some reason the drive works fine for the 2+ hour sync 
procedure but will generally fail out of the raid if I forget and leave 
it connected through the nightly backups.  My guess is that it isn't 
doing as many retries on soft errors or timeouts as a raid member as a 
standalone device would.

-- 
   Les Mikesell
    lesmikesell at gmail.com




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