Steve Lord <lord@xxxxxxx> wrote:
> I have been out for a while, or I would have posted something on this earlier.
> The default mkfs options for xfs are not optimal for heavy I/O load, they are
> somewhat historical and should probably be changed.
> On mkfs try some options like this:
> mkfs -t xfs -f -l size=32768b /dev/xxx
> on mount use these extra options:
> logbufs=4,logbsize=32768
> The first will make the on disk log bigger which helps metadata intensive
> loads not become purely log bound - every request for log space ends up
> having to flush metadata to disk. The mount options allow more log writes
> to be in progress at once.
ok - retried with those options (16384 in my case because 32k was
too big for my small 700m test partition) and the dbench results
got back to normal ... how about increasing those numbers by
default a bit? - would there be any negative side-effects
from doing so?
> These should help XFS performance here, I suspect, but have not tried that
> this will also help:
> echo 5000 > /proc/sys/vm/pagebuf/flush_int
> This will make the interval between dirtying file data and flushing it to
> disk closer to that used by ext2. One of the issues with dbench is files
> getting removed shortly after they are created, you can get mush better
> performance if the removal happens before the data goes out to disk.
will try this too now
lots of thanks
t
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innominate AG
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