[Lustre-discuss] Lustre + qemu/kvm issue

Danny Sternkopf danny.sternkopf at csc.fi
Mon Oct 15 01:15:14 PDT 2012


I wonder if there is anyone out there who has a working test or even
production environment using Lustre for VM disk images?

I run into the Lustre Direct I/O problematic which requires the
application to read and write in 4K I/O chunks. qemu/kvm uses 512 byte
as I/O size and refuses to start the VM. In this case cache is "none".
If I change the cache mode to writethrough (default) then the VM stored 
on Lustre can be started, but it has very poor write performance.
(100-times worse) Any hints?

Best regards,


More information about the lustre-discuss mailing list