Richard Jones writes:
> Malcolm Beattie wrote:
> >
> >
> > Mounting mine when clean takes 4 seconds. I wonder if you used a 1k
> > block size for your filesystem. That greatly increases the time to
> > check the bitmaps upon mounting (though you can turn this off with
> > mount -o check=none). It also greatly decreases the performance of
> > the filesystem.
>
> Quite probably, if that was the default. Can you
> point me to any other things I should be changing
> (eg. stripe size, in particular). Given the myriad
> different possibilities and very limited time, I
> didn't experiment to choose optimal block size or
> stripe size.
>
> I don't have the bonnie benchmarks to hand, although
> they were quite acceptable - bottom line was 13 MBytes/sec
> throughput IIRC. I posted them on linux-raid before,
> so you should be able to dig them up from the archives.
The only archive of this list that AltaVista found me was a local one
which didn't go back far enough. I suggest you look at your "Random
Seeks" figure in bonnie, not the bandwidth figures. I would suggest
recreating the whole thing from scratch with
chunk-size 64
in your /etc/raidtab. Then use
mke2fs -b 4096 -R stride=16 /dev/md0
to create the filesystem (and wait until /proc/mdstat shows the
rebuild has finished). Then try bonnie again and see if the "Random
Seeks" figure has improved. Then try putting on lots of data and
testing fsck times. Oh, and since you're not using SCSI disks, check
that "hdparm /dev/hda" (and the other disks) shows you have using_dma
and unmaskirq set to 1.
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Unix Systems Programmer
Oxford University Computing Services
