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Re: Solved: slow performance CEPH RBD on KVM


Cool, I didn't consider this as a variable :)

IDE works extremely slow indeed... anyway, make sure to also have RBD
caching on KVM side.

Cheers

On Mon, Aug 6, 2018, 14:51 Benjamin Naber <benjamin.naber@xxxxxxxxxxxxxx>
wrote:

> Hi Andrija,
>
> i figured out the problem. templates should be created as OS: Other PV
> Virtio-SCSI (64-bit) otherwise, vm disk will created as an IDE Device.
>
> Afther changing the setting i got my Performance and a well working
> environment.
>
>
> Kind regards
>
> Ben
>
> >
> >     Andrija Panic <andrija.panic@xxxxxxxxx> hat am 5. August 2018 um
> 11:05 geschrieben:
> >
> >     Hi,
> >
> >     Google "enable rbd cache on KVM" - this is supposed to enable write
> back
> >     cache if client OS sends proper flush commands (i.e. linux kernel
> newer
> >     than 3.0) - will NOT help with reads, obviously...
> >
> >     For rest, there can be done some tunning, but expect no miracle.
> >
> >     You didn't specify ceph cluster details, journals setup, etc - would
> be
> >     useful to know, then KVM host version, etc.
> >
> >     Cheers
> >
> >     On Fri, Aug 3, 2018, 16:05 Benjamin Naber <
> benjamin.naber@xxxxxxxxxxxxxx>
> >     wrote:
> >
> >         > >
> > >         Hi @all,
> > >
> > >         ive setup a Ceph Cluster in combination with KVM Hosts. If i
> benchmark
> > >         ceph rbd performance from Hypervisor itself i got 10 times
> higher
> > >         performance than from using a cloudstack created guest-vm.
> > >         are there any recommendet settings for KVM Hosts in cloudstack
> or KVM
> > >         using with ceph rbd ?
> > >
> > >         kind regards
> > >         Ben
> > >
> > >     >
>