Hi! I have a question about nfs-performance. I don''t where the problem is. My setup: Host dom0 with 8TB harddisk space 8GB RAM and 6 core CPU. The hard disk raid is fast: <cut> root@midas-phalanx:/data# time dd if=/dev/zero of=test.null bs=1M count=1024 1024+0 Datensätze ein 1024+0 Datensätze aus 1073741824 Bytes (1,1 GB) kopiert, 3,27874 s, 327 MB/s real 0m3.303s user 0m0.004s sys 0m1.792s </cut> so the write performance is very good on harddisk. I created several domU guests which do a nfs-boot from the local host. (strange setup, I know). I don''t want to define the size of guests disk so I don''t want to use a image as hard disk image. This is why I do a nfs-boot. The dom0 exports the file system for the guest. I use network bridging. My guest config file is the following: <cut> kernel = ''/boot/vmlinuz-2.6.32-5-xen-amd64'' ramdisk = ''/boot/initrd.img-2.6.32-5-xen-amd64'' memory = 1024 name = ''ufp-mysql-01'' hostname = ''ufp-mysql-01'' #dhcp = ''dhcp'' vif = [ ''mac=00:16:3e:00:42:06, bridge=lan'' ] interface = ''eth0'' ip = ''10.10.42.206'' netmask = ''255.255.255.0'' gateway = ''10.10.42.204'' nfs_server = ''10.10.42.108'' nfs_root = ''/data/nfs-root/ufp-mysql-01'' root = ''/dev/nfs'' extra = ''2 console=hvc0 xencons=tty boot=nfs rootfstype=nfs'' </cut> The guest boots without error. But the write performance over the nfs is very poor: <cut> root@ufp-mysql-01:~# time dd if=/dev/zero of=test.null bs=1M count=512 512+0 Datensätze ein 512+0 Datensätze aus 536870912 Bytes (537 MB) kopiert, 2159,08 s, 249 kB/s real 35m59.133s user 0m0.000s sys 0m1.396s </cut> The read-performance is good: <cut> root@ufp-mysql-01:~# dd if=test.null of=/dev/zero bs=1M 512+0 Datensätze ein 512+0 Datensätze aus 536870912 Bytes (537 MB) kopiert, 0,705893 s, 761 MB/s </cut> But it is not the performance of the server itself: <cut> root@ufp-mysql-01:~# dd if=/dev/zero of=/dev/null bs=1M count=512 512+0 Datensätze ein 512+0 Datensätze aus 536870912 Bytes (537 MB) kopiert, 0,0655885 s, 8,2 GB/s </cut> OK, this is the setup where the nfs-server is on dom0 and exports the filesystem for domU. When I copy the rootfs to another computer and export it from there (with same export options) I get a lot of more performance. This is the guest bootet from nfs on other server: <cut> root@ufp-mysql-01:~# time dd if=/dev/zero of=test.null bs=1M count=512 512+0 Datensätze ein 512+0 Datensätze aus 536870912 Bytes (537 MB) kopiert, 15,506 s, 34,6 MB/s real 0m15.617s user 0m0.004s sys 0m1.260s </cut> The "external" nfs-server has a single hard disk, so this performance is OK for this config. Can you give me a hint why the perfmance is so bad when I export the fs from dom0? How can i solve this? The server has no I/O jobs while this test was running so the whole performance should be available. Jens _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel