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Re: [zfs-discuss] Why is Solaris 10 ZFS performance so terrible?

Subject: Re: [zfs-discuss] Why is Solaris 10 ZFS performance so terrible?
From: Rich Morris
Date: Thu, 10 Sep 2009 16:35:10 -0400
On 09/10/09 16:17, Bob Friesenhahn wrote:
On Thu, 10 Sep 2009, Rich Morris wrote:

On 07/28/09 17:13, Rich Morris wrote:
On Mon, Jul 20, 2009 at 7:52 PM, Bob Friesenhahn wrote:

Sun has opened internal CR 6859997. It is now in Dispatched state at High priority.

CR 6859997 has recently been fixed in Nevada. This fix will also be in Solaris 10 Update 9. This fix speeds up the sequential prefetch pattern described in this CR without slowing down other prefetch patterns. Some kstats have also been added to help improve the observability of ZFS file prefetching.

Excellent. What level of read improvement are you seeing? Is the prefetch rate improved, or does the fix simply avoid losing the prefetch?

This fix avoids using a prefetch stream when it is no longer valid. BTW, ZFS prefetch appears to work well for most prefetch patterns. But this CR found a pattern that should have worked well but did not.

-- Rich
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