On Sun, Jan 4, 2009 at 11:24 AM, Avi Kivity <[email protected]> wrote: > Alexander Atticus wrote: >> >> Hello! >> >> I have been experimenting with KVM and have been experiencing poor write >> I/O >> performance. I'm not sure whether I'm doing something wrong or if this is >> just the current state of things. >> >> While writing to the local array on the node running the guests I get >> about >> 200MB/s from dd (bs=1M count=1000) or about 90MB/s write performance from >> iozone (sequencial) when I write to a 2G file with a 16M record length. >> The >> node is an 8 disk system using 3ware in a RAID50 configuration. It has >> 8GB >> of RAM. >> >> The guests get much slower disk access. The guests are using file based >> backends (tried both qcow2 and raw) with virtio support. With no other >> activity on the machine, I get about 6 to 7MB/s write performance from >> iozone with the same test. Guests are running Debian lenny/sid with >> 2.6.26-1-686. >> > > qcow2 will surely lead to miserable performance. raw files are better. > best is to use lvm. >
What do you mean with best is to use lvm ? You just say to use raw images on an lvm partition because you can easily resize it ? Or somehow images only use the used space of the raw file when used with lvm ? Or there's some trick to make it ? Thanks a lot, Rodrigo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
