I've been perusing all the backup documents in the wiki and have searched through a lot of the forum discussions regarding backup. I haven't seen any one who indicates they are having the problem we are having though.
We would like to get tape backups of the Zimbra backups (/opt/zimbra/backup), but in it's native state it is just too slow. We think the problem is that the Zimbra backup is producing thousands (probably tens of thousands or more) of small files....and it is negatively impacting the performance of our tape backups.
We currently have a Sun Library with 2 LTO3 drives in it, and this is sitting on 4GB fiber channel. The speed of the hardware is not the issue. We can tar a single large file off to the tape drives at 50-80MB/s. Trying to do the same with a very large subdirectory of Zimbra backups gets us results in the 10-15MB/s range initially, but gradually dropping as time goes on. At times we can see it get well below 1MB/s.
We have 3 mailstores, each with about 250GB of backups on it. Later this Spring we will be adding 2 more mailstores, 13,000 or so users, and probably almost double our backup data(1.5-2TB). We can't realistically back this up at those slow speeds. But that's not the worst part...restores go so much slower than backups that it would probably take weeks to restore these systems if we had to come back from a major disaster.
Our current workaround is to tar /opt/zimbra/backup to another LUN on our SAN, and then backup that single tar file to tape(one for each mailstore)... which goes much faster. This however requires us to have double the storage requirements to hold all the backups and the nightly tars.
So...what is the answer? Has anyone else in a large enterprise environment run into this and found a workaround? I saw somewhere that we could use the '-z' parameter on zmbackup, to zip up the blobs. Will that reduce the number of really small files that get created on a zimbra backup? If so that might solve the problem for us....but I'm not sure. Anyone have any thoughts or discovered a good (very fast) way to archive your Zimbra backups off to tape?