Date: Tue, 9 Aug 2011 17:19:02 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-fs@FreeBSD.org, Jeremie Le Hen <jeremie@le-hen.org> Subject: Re: zfs mirror reads only on one disk Message-ID: <20110809151901.GA7877@felucia.tataz.chchile.org> In-Reply-To: <20110809135212.GA13334@icarus.home.lan> References: <20110809131057.GA53580@felucia.tataz.chchile.org> <20110809135212.GA13334@icarus.home.lan>
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On Tue, Aug 09, 2011 at 06:52:12AM -0700, Jeremy Chadwick wrote:
>
> Performance was a little less than I estimated (I really don't care to
> be honest), but this double-confirms that yes, reads do get split across
> mirror members.
By the way, I tried with the same disk (WD Caviar Black) (not the same
size though) on Solaris 11:
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
1104.5 0.0 141371.6 0.0 0.0 0.9 0.0 0.9 1 95 c5t5d0
extended device statistics
r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device
1101.7 0.0 141014.0 0.0 0.0 0.9 0.0 0.9 1 95 c5t5d0
It can reach 140 MB/s!
> Therefore I cannot explain what you're seeing. Maybe consider upgrading
> to a newer RELENG_8 and ZFSv28 and see if things improve? I wish I had
> a way to confirm this would fix your problem but I do not.
Ok, I didn't know ZFS v28 was MFC'd to RELENG_8. By the way, I see you
switched to the new ata(4) driver according to your device names. Is it
painless to upgrade? I'll give it a try this evening hopefully.
Thanks.
Regards,
--
Jeremie Le Hen
Humans are born free and equal. But some are more equal than others.
Coluche
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