[zfs-discuss] Slow read performance

Gionatan Danti g.danti at assyoma.it
Mon Apr 2 15:27:22 EDT 2018


Il 02-04-2018 16:53 Richard Elling ha scritto:
> 
> 1MiB / 8 = 128kiB
>  -- richard

Sure, but the OP stated that both using 128K recordsize and 16M 
recordsize changed nothing.
Moreover, with working prefetch, I (naively?) expect more blocks to be, 
well, pre-fetched, leading to I/O coalescing (ie: 2x128K reads becoming 
1x256K read). Is this expectation wrong?
Finally, how ashift=9 produce better streaming results?

Thanks.

-- 
Danti Gionatan
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Assyoma S.r.l. - www.assyoma.it
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