On 03/21/11 12:20 PM, Richard Elling wrote:
On Mar 20, 2011, at 3:02 PM, Ian Collins wrote:
On 03/20/11 08:57 PM, Ian Collins wrote:
Has anyone seen a resilver longer than this for a 500G drive in a riadz2 vdev?
scrub: resilver completed after 169h25m with 0 errors on Sun Mar 20 19:57:37
2011
c0t0d0 ONLINE 0 0 0 769G resilvered
I didn't intend to start an argument, I was just very surprised the resilver
took so long.
I'd describe the thread as critical analysis, not argument. There are many
facets of ZFS
resilver and scrub that many people have never experienced, so it makes sense to
explore the issue.
Expect ZFS resilvers to take longer in the future for HDDs.
Expect ZFS resilvers to remain quite fast for SSDs.
Why? Because HDDs are getting bigger, but not faster, while SSDs are getting
bigger and faster.
I've done a number of studies of this and have a lot of data to describe what
happens. I also
work through performance analysis of resilver cases for my ZFS tutorials.
Does the throttling improve receive latency?
The 30+ second latency I see on this system during a resilver renders it
pretty useless as a staging server (lots of small snapshots).
--
Ian.
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