I have used other products in the past for backup (NBU, Arkeia, Legato, and the old standbys (tar, star, cpio, et al). I was on the hunt for a good low cost backup solution for a few (read < 5) servers that have very large data sets on them. I am not opposed to commercial Zmanda but don't like the subscription only model (assuming that if I don't continue to pay every year I loose the software & web license of the last version I had while under support?)

Anyway, since I haven't seen any real examples of people using Amanda for large scale use, I was hoping that someone would chime in here to validate 1) it works ok and 2) the performance doesn't suck (i.e. long backup times). With a corollary question about if amanda supports multiple tape drives used per job in an automatic fashion (i.e. to write file x to drive 0 and file x+1 to drive 1; and keep alternating). I've done the manual method (pointing streams to each drive) but that does not scale as well for reducing backup time.

- 40 to 50TiB / ~5,000,000 files per server
Quarterly Full backups
Daily differentials to tape pool that gets rotated offsite weekly

- tape drive is LTO-4 technology (Quantum Scalar 50)

- Maintain 3 full backups
- last full backup on-site
- n-1 backup offsite
- n-2 backup in transit to become the next full n backup

- Differentials
- keep n pool onsite
- n-1 through n-11 pools offsite
- n-12 in transit to become the next 'n'

Since these are large systems I figure that running the Amanda server & client local on each would be the most efficient (avoid network latency & bandwidth issues). Assuming a staging drive is needed was thinking of a couple SSD's (say 200-400GiB total space) as that would be the only thing fast enough to really keep up. Each system itself has 4 channels going to 64-128 spindles and has no problems pushing the 120MiB/s to a tape drive (could probably feed 4 drives for most of the backup but some directories have a lot of lookups which would lower it down to about 120-140MiB/s of a single drive).

Anyway anyone have any experience/comments on large single server setups and amanda's suitability for it?