Disc (De)Fragger

[P. Brouwer]

In <1991May01.154043.1031 at scuzzy.in-berlin.de> src at scuzzy.in-berlin.de (Heiko Blume) writes:

>stevedc at syma.sussex.ac.uk (Stephen Carter) writes:
>>		Disc Fragmentation (etc)

>for system V machines:
>i regularly use a program called packdisk on my /usr/spool/news.
>another program called fsanalyze tells me that the above filesystem
>takes about two weeks to develop >40% fragmentation. packdisk makes
>that ~3% again. packdisk was posted to comp.sources.misc, volume8,
>fsanalyze is in volume5. of course packdisk is somewhat dangerous :-)

This program has one disadvantage: It reformats the disk with a mkfs gap size
of one. For most scsi disks this is okee but for ESDI this might result in a
slow down of the diskthroughput.
fsanalyze used the gap value from the superblock which is set to one by
packdisk. So you will not notice it.
If you are not sure if this is the correct gap value for your disk find a spare
partition. Execute a mkfs with a gap of 1 . Use the bonnie disk benchmark to
measure the disk throughput. Do this sequence for different gap sizes.
The diskthrough put for sequential IO should give an optimum somewhere.

--
#  Peter Brouwer,                | Philips Information Systems,                #
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