Re: Backup plan and big filesystems

owner-amanda-users AT amanda DOT org a écrit sur 21/08/2006 16:45:18 : > Jon LaBadie wrote: > [snip] > > If go with amanda you definitely should do that GFS filesystem as > > multiple DLEs. If I got your data size correct, you have about > > 1 TB of GFS data plus 0.4 TB of misc OS data, about 1.4TB total. > > This in the case I will decide to split the actual filesystem into more > than one, that means I will need to create multiple DLEs. > > But if I stick with just one big GFS fs, I think I will have just one > DLE and then Amanda will take care to span the tar volume into multiple > tapes, when it receives an end-of-media message. Please correct me :-)

Yes, but AFAIK that's a rather new feature that doesn't look easy to set up (that's my stupid newbie opinion :-).
>
(snip: don't understand)
> > Now, what it mainly concerns me, are the off-site tapes. > > Like you said probably the best way to go would be having two different > tape sets: 1 for incremental+fullweekly, and 1 for fullweekly to be > taken off-site.

It's not exactly what I said.

I said:

1 set for incremental only + 1 set for full only.
You never export the incremental set; it stays forever in your robot.
Your full-only set is made of 2 times the number of tapes needed for a full dump.

Every week, Amanda uses half of your "full tapes" to do its full backups and every week you replace these tapes by the other one from the "full set".

This way you have a weekly full off-site.

And Amanda reports tell you exactly what tape it used and what tape it expect.

example of Amanda report (from my config):

These dumps were to tape daily-backup05. The next tape Amanda expects to use is: daily-backup06. STATISTICS: Total Full Daily -------- -------- -------- Estimate Time (hrs:min) 0:16 Run Time (hrs:min) 1:42 Dump Time (hrs:min) 1:26 1:18 0:08 Output Size (meg) 99549.4 93266.7 6282.7 Original Size (meg) 99549.4 93266.7 6282.7 Avg Compressed Size (%) -- -- -- (level:#disks ...) Filesystems Dumped 23 15 8 (1:8) Avg Dump Rate (k/s) 19865.0 20498.5 13617.2 (ndlr: wow so sloooow!) Tape Time (hrs:min) 1:26 1:18 0:08 Tape Size (meg) 99549.4 93266.7 6282.7 Tape Used (%) 22.1 20.7 1.4 (level:#disks ...) Filesystems Taped 23 15 8 (1:8) Avg Tp Write Rate (k/s) 19838.7 20469.8 13609.9 USAGE BY TAPE: Label Time Size % Nb daily-backup05 1:26 99549.4 22.1 23

The downside is that the "incremental only" tapes are under-used.

However, John estimated that your daily dumps would be about 300GB large if your DLE were correctly balanced. In that case, having a weekly full off-site would only require 2*7=14 LTO3 tapes. Isn't that good enough?