ZFS write speed
S.N.Grigoriev
serguey-grigoriev at yandex.ru
Thu Oct 28 07:30:06 UTC 2010
28.10.10, 01:54, "Stefan Bethke" <stb at lassitu.de>:
> Am 27.10.2010 um 22:51 schrieb S.N.Grigoriev:
>
> > Hi list,
> >
> > I've got very low write speed using ZFS on a SATA disk.
> > My HDD configuration is:
> > ad4: 70911MB at ata2-master UDMA100 SATA 3Gb/s
> > ad6: 78532MB at ata3-master UDMA100 SATA 1.5Gb/s
> > ad8: 1430799MB at ata4-master UDMA100 SATA 3Gb/s
>
> The EARS has 4k sectors, if I'm not mistaken. I don't recall the eventual
> outcome, but there was a long thread on stable or hackers on how to ensure
> proper alignment and (minimun) 4k-sized writes to make sure the disk doesn't
> have to do a read-modify-write cycle, so try and search the archives.
Stefan,
thank you for your response. I'll try to find the topic you pointed.
> > ad4 and ad6 are single-slice disks (UFS2 with soft updates)
> >
> > ZFS configuration is following:
> > zpool create Z ad8
> > zfs create Z/music
> > zfs create Z/video
> > All ZFS parameters are default.
> > kern.maxvnodes = 1000000
> >
> > To test my configuration I recursively copied from ad6 to ad8 two directories.
> > The first one contains MP3 files (average size = 10MB).
> > The second one contains AVI files (average size = 1GB).
> >
> > To compare performance I repeated above tests with ad8 using UFS2 with soft updates.
> >
> > 18GB of MP3 files required 10m35s to copy to UFS2 and 21m40s to copy to ZFS.
> > 30GB of AVI files required 16m6s to copy to UFS2 and 1h2m39s to copy to ZFS.
> >
> > I used for tests FreeBSD 8.1R amd64. Amount of RAM on my machine is 6GB.
> >
> > Any tips?
> >
> > --
--
Regards,
Serguey.
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