Tape backup performance on 386 ISA/EISA systems

[Ron Kuris]

In article <1990May25.123302.26061 at virtech.uucp> cpcahil at virtech.uucp (Conor P. Cahill) writes:
>I am trying to collect data on the performance of the different tape
>backup systems available for 386 bases Unix systems.  What I am
>trying to obtain is the speed in MB/minute of backing up a file system
>to tape.  In order to be meaningful, the file system must be at least
>30MB and be backed up using the following command (so that everybody
>uses the same mechanism):
>
>	/bin/time sh -c "find . -print | cpio -oBcC 10240 > /dev/rmt0"
>
>Note that you may adjust the block size (10240) as you feel is appropriate
>for your system as long as you tell me what you used.  Obviously you might
>also need to change the tape device name.
>
> [ stuff deleted ]
Seems to me like you're not taking into account filesystem fragmentation
or a bunch of other factors.  How about running a disk optimizer (e.g.
shuffle) before you start the test?  I've noticed a dramatic increase due
to less head activity (I don't have numbers handy).
-- 
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