Hi list,
I have a question about CFQ scheduler and the old warning one can find
on the faq page: "As of kernel 3.2.12, the default i/o scheduler, CFQ,
will defeat much of the parallelization in XFS".
Can I ask for more information about the bad interaction between CFQ and
XFS, and especially why it does defeat filesystem parallelization? Is
this warning still valid? What about the newer BFQ?
Note: I always used deadline or noop with XFS, but I am facing a disk
with random read starvation when NCQ is enabled and a mixed sequential &
random load happens. So far I saw that the only scheduler (somewhat)
immune to the issue is CFQ, probably because it does not mix IO from
multiple processes (it issue IO from one process at time, if I
understand it correctly).
Thanks.
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx
GPG public key ID: FF5F32A8
