I was hoping to avoid rsync/rdiff because the snapshot volume itself was a list of differences over the last 24 hours.
It is whispered that Greg Freemyer was heard, on or about 1/27/2004 6:29 PM to say:
On Tue, 2004-01-27 at 18:03, Chris Beck wrote:
Hi! I've been looking through the archives and I can't see anything addressing my issue. Probably because I didn't look hard enough.
I want to use 24-hour snap shots as an archival tool.
I have 2 identical file servers, one primary and one as an off-site mirror. I'd like the primary system to generate a transaction log that rolls over every 24-hours and gets transmitted to the remote site. After 7 days on the remote site, the log gets triggered so the remote is always 7 days out of sync but with the last 6 days logs ready to go. I could have it auto update on arrival, but I was thinking that allowing a week for someone to realize that they deleted something vital would be a good thing(TM) - standard archiving stuff I guess.
Do you think that lvm snapshot volumes are a simple and convenient way of doing this? Does this make sense at all?
Thanks,
Chris
The above transaction log is new to me. I have seen that done with databases, but not with generic fileservers.
If I was trying to accomplish what I think are your goals, I would use rdiff-backup.
I don't know the syntax offhand, but the process would be:
Create snapshot
mount snapshot as /snap
rdiff-backup /snap //backup_server/snap rdiff-backup --delete_older_than 7-days //backup_server
rdiff-backup uses technology similar to rsync to ensure only the deltas are sent between the servers. (ie. first check datestamps etc. to see if file changed. If so, use md5sums to isolate what parts of the file changed and send them between the servers.)
It maintains a current copy of the source files, and a series of diffs to go backwards to older versions of the files. In the above it would keep a max of 7 diffs per file. If you wanted to restore from 7 days prior, rdiff-backup would internally have to apply all 7 diffs, one after another.
rdiff-backup has lots of other features/capabilities.
Also, it uses ssh to encrypt all data between the servers, so it is also fairly secure.
The only problems I have with rdiff-backup are:
1) ACL and EA support is only in the Unstable release, but they seem to be working fine
2) rdiff-backup is written in python and when an unhandled error occurs, it dumps out a stack trace. To see what the problem is you have to go thru the stack trace and the code. Not to bad if you have some programming skills. If not, the mailing list is fairly responsive.
There is a wiki at http://rdiff-backup.solutionsfirst.com.au/index.php?RdiffBackupWiki
Greg
-- Chris Beck / Y.A.B.A. / Fungal Genomics CFSG / Concordia University "La loi dans sa majestueuse ÃgalitÃ, interdit à tous, aux riches comme aux pauvres de dormir sous les ponts, de coucher dans la rue et de voler du pain." -- Anatole France (Les Lys Rouge - 1894)
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