Amanda-Users

Writing to tape performance issue?

2007-01-05 16:07:18
Subject: Writing to tape performance issue?
From: "Mark Hennessy" <mhennessy AT cloud9 DOT net>
To: <amanda-users AT amanda DOT org>
Date: Fri, 5 Jan 2007 15:53:32 -0500
Many thanks for the answers to my previous questions.  I'm just trying to
iron out a few minor issues with my backup cycle at this point.

It would appear that based on the "Tape Time" value provided in the report
that the rate at which data are written out to the tape is 3.7 MB/s.  The
drive is rated by the manufacturer at 11 MB/s or 22 MB/s, so it would seem
that 3.7 MB/s is a bit slow, yes?  Is "Tape Time" solely the time that Amanda
is writing dumps directly to tape?  Does that include other interactions that
would add a substantial amount of time as well?

I'm using Amanda 2.5.1p2 on FreeBSD 6.1 and a Quantum SDLT220 drive.

STATISTICS:
                          Total       Full      Incr.
                        --------   --------   --------
Estimate Time (hrs:min)    2:03
Run Time (hrs:min)         8:24
Dump Time (hrs:min)        8:55       3:03       5:52
Output Size (meg)       72003.2    36673.6    35329.6
Original Size (meg)     72003.1    36673.6    35329.5
Avg Compressed Size (%)     --         --         --    (level:#disks ...)
Filesystems Dumped           60         11         49   (1:49)
Avg Dump Rate (k/s)      2298.6     3425.6     1713.4

Tape Time (hrs:min)        5:24       1:07       4:17
Tape Size (meg)         72005.8    36674.1    35331.8
Tape Used (%)              71.0       36.2       34.9   (level:#disks ...)
Filesystems Taped            60         11         49   (1:49)

Chunks Taped                  0          0          0
Avg Tp Write Rate (k/s)  3793.3     9408.1     2342.3

USAGE BY TAPE:
  Label       Time      Size      %    Nb    Nc
  VOL13       5:24    72006M   71.0    60     0

--
 Mark Hennessy


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