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[Qemu-devel] [Bug 568445] Re: LVM backed drives should default to cache=
Jamin W. Collins
[Qemu-devel] [Bug 568445] Re: LVM backed drives should default to cache='none'
Sat, 14 Aug 2010 05:31:26 -0000
Can't seem to find anything in the upstream changelogs or source to
indicate that such a change was made.
LVM backed drives should default to cache='none'
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Status in QEMU: Invalid
Status in “virt-manager” package in Ubuntu: Triaged
Binary package hint: virt-manager
KVM guests using LVM backed drives appear to experience fairly high iowait
times on the host system if the guest has even a moderate amount of disk I/O.
This translates to poor performance for the host and all guests running on the
host, and appears to be due to caching as KVM defaults to using writethrough
caching when nothing is specified. Explicitly disabling KVM's caching appears
to result in significantly better host and guest performance.
This is recommended in at least a few places: