[Gluster-devel] Re: [Gluster-users] I/O fair share to avoid I/O bottlenecks on small clsuters

[Gordan Bobic]

> Ran wrote:
>>> The line that you need to add is the one with "writeback" in it.
>>> If you are running qemu-kvm manually, you'll need to add the 
>>> "cache=writeback" > to your list of -drive option parameters.
>>> All of this, of course, doesn't preclude applying ionice to the qemu 
>>> container processes.
>>
>> ionice has no affect on network mounts just local disks
>> so basicly its useless to ionice the kvm proccess wich takes its IO
>> from gluster rather then local disk .

Something just occurred to me. You are running separate volumes for your 
different services, right? A separate glfs volume for your mail spools / 
Maildirs, VM image storage, etc?

If that is the case, then you should be able to ionice the glfs 
processes on the server accordingly. If you are finding that the VM 
images are causing a lot of I/O load relative to other things, you could 
"ionice -c3" the glfs daemon running that particular volume.

Gordan