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it@ucb.com.au
October 6th, 2011, 08:41 PM
Hi, wondering what the benefit of using an amanda client on a Linux server as against using a mounted share. Due to using snapshots, the backup server to date has not used any clients. We are currently backing up a remote share as it looks like a local file system to the backup server. Is there any speed advantage to using a backup client and why (if someone knows)

Thanks

dougmc
October 17th, 2011, 12:02 AM
I don't completely understand what you mean when you say "due to using snapshots, the backup server to date has not used any clients. "

That said, I can say why one might prefer a local backup client to backing things up via NFS.

NFS is generally slower than local disk. (By generally, I mean just about always if everything else is equal. Though often everything else isn't equal.)

If you're backing up a remote NFS share, root permissions are often quashed, so if a file isn't readable by "nobody", the backup won't pick it up.

If a filesystem is changing rapidly, NFS caching may cause what the client sees to be somewhat delayed.

Though if you've configured amanda to write it's backups to a NFS share on a remote system, only the performance issue is likely to be an issue -- and even that might not be a concern.

it@ucb.com.au
October 25th, 2011, 04:29 PM
I have an answer to my own question. Using a Zmanda Linux backup agent effectively doubles the throughput of the backup. We've purchased the additional client. (We are of NFP charity and every dollar counts which is why I was asking the question in the first place)

With regard to snapshots, all our servers are virtualised using XEN under SuSE Linux. Every day, we take an LVM snapshot of all our server images, both Linux and Windows and save the snapshot to a file. This file is then backed up to tape. Using a restore from tape, (which can take an hour or so) we can resurrect a damaged server in about 20 minutes in the very worst case. If something goes wrong with a patch, a virus or misconfiguration, it's often quicker to reinstate a snapshot and try and fix the damaged server. While this rarely happens, it's wonderful to have. Using snapshots, we backup all 30 servers and data completely every day. Zmanda plays a part in this.

Regards
Eric.