Re: [Jfs-discussion] first experiences with JFS

[<pg...@jf...>]

>>> On Thu, 15 Sep 2005 08:38:16 -0500, Dave Kleikamp
>>> <sh...@au...> said:

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>> * Making a file system with a 30MiB log instead of the default
>>   32MiB makes reading it with 'tar' over twice as slow. This
>>   for the same partition on the same hard disc with the same
>>   content freshly loaded (it was so strange I checked several
>>   times).

shaggy> You're right that this is strange.  If you are running
shaggy> with noatime, the journal shouldn't be a factor at all
shaggy> when reading the volume.  This one really puzzles me.

I wasn't running with 'noatime', but not to worry. I think it
was due to some ATA chipset driver issue, because I have tried
to reproduce it later and it did not happen again.

However from various tests it looks that when reloading a
filesystem from fresh the size of the log seems to have a
_small_ (e.g. 10%) influence on how ''fast'' rereading the
contents back is. If the log is longer perhaps allocations
are more contiguous or whatever...

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