Here I am with a new performance test with Sheepdog 0.6.0_127_g085568a. I don't understand the reason, but write speed with cache enabled is the same as without cache. The host where I'm running the guest has this configuration: sheep -w size=20000 /mnt/sheep/meta/,/mnt/sheep/dsk02 /dev/sda3 on /mnt/sheep/meta type xfs (rw,relatime,attr2,delaylog,noquota) /dev/sdb1 on /mnt/sheep/dsk02 type xfs (rw,relatime,attr2,delaylog,noquota) sda is and ssd disk! The guest qemu-system-x86_64 -name backup -enable-kvm -drive file=sheepdog:backup,cache=writeback -drive file=sheepdog:backup_data,cache=writeback ... dd if=/dev/zero of=c1 bs=1M count=512 oflag=sync 512+0 record dentro 512+0 record fuori 536870912 byte (537 MB) copiati, 63,3792 s, 8,5 MB/s I'm writing into sheepdog:backup_data (1T), also formatted with xfs. The other two hosts have almost the same configuration: sheep -w size=20000 /mnt/sheep/dsk01,/mnt/sheep/dsk01/obj,/mnt/sheep/dsk02 /dev/vg00/sheepdog /mnt/sheep/dsk01 xfs defaults,noatime 0 2 /dev/sdb1 /mnt/sheep/dsk02 xfs defaults,noatime 0 2 No ssd here. The performance is exactly the same. |