Date: Mon, 23 Jan 2017 15:37:31 +0000 From: Pete French <petefrench@ingresso.co.uk> To: petefrench@ingresso.co.uk, stable@freebsd.org Subject: Re: Horrible zpool resilver perormance on local hast Message-ID: <E1cVggV-0004e0-GK@dilbert.ingresso.co.uk> In-Reply-To: <E1cVgJH-0004aA-Kk@dilbert.ingresso.co.uk>
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Partially answering my own question here, as it occured to me that the zpool is scattering writes across the disc in 4k blocks, but hast has a minimum extent size of 2meg by default. Thats eems like a likely culprit for the 'dirty blocks' multiplcation I am seeing. I shrunk down the extent size to 16k to see if that helped, and I now see a far smaller dirty block to written block ration, but also the write speed has now shrunk down even more to around 50k/s :-( Any advice on tuning this properly ? -pete.
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