After noodling and experimenting various strategies of how to "offsite"
2TB of backup data, I am using the following method with dd_rescue (dd
that continues on failures):
Paths
* /export/backups (the BackupPC TOPDIR and pool)
* /export/offsite (a 2TB partition of drives in removable trays)
Procedure
* /etc/init.d/BackupPC stop (sometimes I need to reboot to get
rid of residual processes)
* umount /export/backups (backups should not be in use)
* mount /dev/sdc1 /export/offsite (need to have target offsite
volume available)
* dd_rescue -v /dev/sdb1 /export/offsite/backups.img
To restore
* dd_rescue -v /export/offsite/backups.img
OR (to just restore a few files or poke around the offsite backups)
* mkdir /export/loop
* mount -o loop /export/backups/backups.img /export/loop
This is the first iteration of the above procedure, but looks promising.
The dd_rescue seems to be able to xfer around 200GB+ an hour so I expect
my offsite image to be built in 9-10 hours. Does anyone see any glaring
holes in this methodology? As a side benefit for you guys who might
have enough disk space on your offsite volume is the ability to hold
multiple backup images, I unfortunately do not have this luxury :-)
/Christian
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rob
Owens
Sent: Monday, July 16, 2007 11:38 AM
To: [email protected]
Subject: [BackupPC-users] [Fwd: Re: Backing up the Backup Directory]
Forwarding this to the list because I accidentally took the thread
private.
-Rob
Rob Owens wrote:
> Les,
>
> In the past you've talked about using software RAID 1 with hotplugable
> drives. Have you tried it? Does it work well? And would it work
> with USB drives?
Yes, the way I am doing it is with a Linux software RAID1 created with 3
members with one specified as 'missing'. There are 2 internal drives
that always stay in sync, and a pair of external drives that are rotated
in weekly as the 3rd member, then when the sync is completed I briefly
stop backuppc, unmount the partition, then fail and remove the external
drive from the raid. This does work and I think it is reliable. You
can leave it mounted while while the sync happens although it slows down
a lot if a backup is running. I use dual interface firewire/USB external
drives that normally take about 2 hours to sync a 250 gig partition over
firewire, and can mount it via USB in my laptop for immediate restores.
The server only has USB1.1, otherwise it would probably work to sync
over USB instead.
Originally I tried using only a single internal drive and keeping one of
the external drives in the RAID all the time, but had problems with the
Linux firewire drivers making the drive fail during backups. Switching
to the sync-and-remove operation works around this issue. I also had an
internal drive fail in this configuration which kept the sync from ever
completing. I was able to recover (losing a week's backups) by moving
the disk from the swapped-out external case to an internal position, but
didn't want to have to repeat that so I added the 2nd internal full time
RAID member.
I have most of the parts in place to set up a new system with 750 gig
drives in swappable SATA carriers but haven't decided yet whether to
repeat the 3-member RAID1 or to try LVM on a 2-member RAID where the
copy procedure would be to briefly unmount and make an LVM snapshot,
then image-copy the snapshot to the drive that will be swapped. The
result should be about the same either way, but I'm not sure about the
speed of the copy.
--
Les Mikesell
[EMAIL PROTECTED]
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