At Tue, 19 Jul 2011 11:30:57 +0200, Benjamin Cleyet-Marrel wrote: > > Hi, > > We are currently in the process of evaluating sheepdog to use as a > backend storage for our virtual environement. > But right now I am facing really poor performances on unallocated bloc. > It litterraly takes hours to convert a 5G file. > > So I am mounting the partition with different option without any luck > /dev/sdd1 on /var/lib/sheepdog type ext4 > (rw,noatime,user_xattr,barrier=0,data=writeback,nobh) > Started sheepdog with > sheep -p 7000 -l 0 /var/lib/sheepdog > > When I issues > qemu-img convert /images/debian60-64bits.qed -O raw sheepdog:debian60-64bits > > It takes hours to finish altought it is just 5G img. > The performance from within the virtual machine is then fine. and close > to raw performances. > > Is there something I am doing wrong ? Is the write cache enabled on your disk? What is the result of 'hdparm -W /dev/sdd'? Currently, Sheepdog works in a writethrough mode always, but other formats work in a writeback mode when converting images. So if the write cache is not enabled on your disk, I think it causes a severe difference. Thanks, Kazutaka |