Hello all.
I have an amanda system working well, using DDS-4 tapes to back up 20
disks on 6 hosts. The tapebackup host used to run from my office, using
a hub with two other, low-traffic hosts to backup the other hosts in our
server room across a 100base-T line connected to a Cisco switch. In this
configuration, backups typically took 4-6 hours.
I then moved the tapehost into the server room, where it uses a
dedicated 100base-T line directly into the switch. As far as I can
remember, this is the only change to the system. Now, backups typically
take 15-24 hours, and I frequently (once a week or so) have to interrupt
the previous day's backup and flush, to do today's backup.
Is my understanding correct that the dump phase runs concurrently on
all the hosts at the same time? Then, the hosts transfer the backup to
the tapehost. Is this concurrent, too? Finally, the tapehost spools to
the tape, for which there's just one instance.
Is there any way to determine where all the time is being spent? I
remember using amstatus while a dump was under way, and seeing stats
about what percentage of time was spent waiting for processes to
complete. However, it looks like the amstatus is erased after the run
completes.
Any suggestions on diagnosing this problem? This isn't an urgent
problem for me, but I would like to understand it and correct it.
Here's part of yesterday's amanda report, which ran for more than 24
hours:
STATISTICS:
Total Full Daily
-------- -------- --------
Estimate Time (hrs:min) 0:09
Run Time (hrs:min) 1:12
Dump Time (hrs:min) 21:45 21:23 0:22
Output Size (meg) 3283.8 3244.4 39.4
Original Size (meg) 7779.2 7518.4 260.9
Avg Compressed Size (%) 41.8 42.7 14.9 (level:#disks
...)
Filesystems Dumped 19 4 15 (1:15)
Avg Dump Rate (k/s) 42.9 43.1 30.9
Tape Time (hrs:min) 1:03 1:01 0:02
Tape Size (meg) 3284.8 3244.6 40.2
Tape Used (%) 28.4 28.0 0.3 (level:#disks
...)
Filesystems Taped 19 4 15 (1:15)
Avg Tp Write Rate (k/s) 887.6 906.7 328.7
Here's the only variables in the config that I think would affect
this:
netusage 1200 Kbps # maximum net bandwidth for Amanda, in KB per
sec
Thanks for your thoughts and suggestions on this.
-Kevin Zembower
-----
E. Kevin Zembower
Unix Administrator
Johns Hopkins University/Center for Communications Programs
111 Market Place, Suite 310
Baltimore, MD 21202
410-659-6139
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