Hi list, I''m using a Compaq Proliant DL385G2, with two dual-core HE Opteron CPU''s, 16G memory and a bunch of 146G SAS disks in a hardware raid configuration. The machine is running SLES10SP1. I created some LVM partitions to use in my Xen guests. When I mount these partitions in domU, performance is quite good. When I use them in a guest, however, write performance is really poor. I tried ReiserFS, ext3 and ex3 mounted as ext2, but that really doesn''t make any difference. Below are two typical results of a run with bonnie with a 2G file. All values are in MB/s. On domU: Char write: 58 Rewrite: 239 Block write: 711 Char read: 68 Block read: 1283 On Guest: Char write: 31 Rewrite: 7 Block write: 38 Char read: 65 Block read: 903 I ran these tests multiple times and these values are reproducable. The difference in write performance is obvious. Could anyone shed some light ons this, or provide me with some hints on where to look? Below are the vm config file and dmesg output from the guest. Thanks in advance, roel ---/--- vm config file disk = [ ''phy:/dev/system/vm1system,hda,w'', ''phy:/dev/cciss/c0d0p5,hdb,w'', ''phy:/dev/system/vm1usrsap,hdc,w'', ''phy:/dev/system/vm1sapmnt,hdd,w'', ''phy:/dev/system/vm1sapdata,hde,w'', ''phy:/dev/cciss/c0d0p6,hdf,w'', ''phy:/dev/system/vm1temp,hdg,w'', ''phy:/dev/system/test,hdh,w'', ] memory = 4096 vcpus = 1 cpus = "2" builder = ''linux'' name = ''vm1'' vif = [ ''mac=00:16:3e:95:1d:66'' ] localtime = 1 on_poweroff = ''destroy'' on_reboot = ''restart'' on_crash = ''restart'' extra = '' TERM=xterm'' bootloader = ''/usr/lib/xen/boot/domUloader.py'' bootentry = ''hda:/boot/vmlinuz-xen,/boot/initrd-xen'' ---/--- dmesg from guest Bootdata ok (command line is TERM=xterm) Linux version 2.6.16.46-0.14-xen (geeko@buildhost) (gcc version 4.1.2 20070115 (prerelease) (SUSE Linux)) #1 SMP Thu May 17 14:00:09 UTC 2007 BIOS-provided physical RAM map: Xen: 0000000000000000 - 0000000100800000 (usable) On node 0 totalpages: 1050624 DMA zone: 1050624 pages, LIFO batch:31 DMA32 zone: 0 pages, LIFO batch:0 Normal zone: 0 pages, LIFO batch:0 HighMem zone: 0 pages, LIFO batch:0 No mptable found. Built 1 zonelists Kernel command line: TERM=xterm Initializing CPU#0 PID hash table entries: 4096 (order: 12, 131072 bytes) Xen reported: 2400.084 MHz processor. Console: colour dummy device 80x25 Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes) Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes) Software IO TLB disabled Memory: 4096256k/4202496k available (1902k kernel code, 97476k reserved, 798k data, 160k init) Calibrating delay using timer specific routine.. 6001.89 BogoMIPS (lpj=12003788) Security Framework v1.0.0 initialized Mount-cache hash table entries: 256 CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) CPU: L2 Cache: 1024K (64 bytes/line) checking if image is initramfs... it is Freeing initrd memory: 7124k freed Brought up 1 CPUs migration_cost=0 DMI not present or invalid. Grant table initialized NET: Registered protocol family 16 Brought up 1 CPUs PCI: setting up Xen PCI frontend stub ACPI: Subsystem revision 20060127 ACPI: Interpreter disabled. xen_mem: Initialising balloon driver. Setting mem allocation to 4194304 kiB PCI: System does not support PCI PCI: System does not support PCI IA32 emulation $Id: sys_ia32.c,v 1.32 2002/03/24 13:02:28 ak Exp $ audit: initializing netlink socket (disabled) audit(1183375183.864:1): initialized VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 512 (order 0, 4096 bytes) Initializing Cryptographic API io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) rtc: IRQ 8 is not free. Non-volatile memory driver v1.2 i8042.c: No controller found. RAMDISK driver initialized: 16 RAM disks of 128000K size 1024 blocksize xencons_init: Initializing xen vfb; pass xencons=tty to prevent this Xen virtual console successfully installed as xvc0 Event-channel device installed. mice: PS/2 mouse device common for all mice input: PC Speaker as /class/input/input0 md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: bitmap version 4.39 NET: Registered protocol family 2 IP route cache hash table entries: 262144 (order: 9, 2097152 bytes) TCP established hash table entries: 262144 (order: 10, 4194304 bytes) TCP bind hash table entries: 65536 (order: 8, 1048576 bytes) TCP: Hash tables configured (established 262144 bind 65536) TCP reno registered NET: Registered protocol family 1 XENBUS: Device with no driver: device/vbd/768 XENBUS: Device with no driver: device/vbd/832 XENBUS: Device with no driver: device/vbd/5632 XENBUS: Device with no driver: device/vbd/5696 XENBUS: Device with no driver: device/vbd/8448 XENBUS: Device with no driver: device/vbd/8512 XENBUS: Device with no driver: device/vbd/8704 XENBUS: Device with no driver: device/vbd/8768 XENBUS: Device with no driver: device/vif/0 XENBUS: Device with no driver: device/console/0 netfront: Initialising virtual ethernet driver. netfront: device eth0 has copying receive path. Registering block device major 3 blkfront: hda: barriers enabled hda: unknown partition table blkfront: hdb: barriers enabled hdb: unknown partition table Registering block device major 22 blkfront: hdc: barriers enabled hdc: unknown partition table blkfront: hdd: barriers enabled hdd: unknown partition table Registering block device major 33 blkfront: hde: barriers enabled hde: unknown partition table blkfront: hdf: barriers enabled hdf: unknown partition table Registering block device major 34 blkfront: hdg: barriers enabled hdg: unknown partition table blkfront: hdh: barriers enabled hdh: unknown partition table ReiserFS: hda: found reiserfs format "3.6" with standard journal ReiserFS: hda: using ordered data mode reiserfs: using flush barriers ReiserFS: hda: journal params: device hda, size 8192, journal first block 18, max trans len 1024, max batch 900, max commit age 30, max trans age 30 ReiserFS: hda: checking transaction log (hda) blkfront: hda: write barrier op failed blkfront: hda: barriers disabled reiserfs: disabling flush barriers on hda ReiserFS: hda: Using r5 hash to sort names Adding 31254416k swap on /dev/hdb. Priority:-1 extents:1 across:31254416k md: Autodetecting RAID arrays. md: autorun ... md: ... autorun DONE. device-mapper: 4.7.0-ioctl (2006-06-24) initialised: dm-devel@redhat.com dm-netlink version 0.0.2 loaded loop: loaded (max 64 devices) ReiserFS: hdc: found reiserfs format "3.6" with standard journal ReiserFS: hdc: using ordered data mode reiserfs: using flush barriers ReiserFS: hdc: journal params: device hdc, size 8192, journal first block 18, max trans len 1024, max batch 900, max commit age 30, max trans age 30 ReiserFS: hdc: checking transaction log (hdc) blkfront: hdc: write barrier op failed blkfront: hdc: barriers disabled reiserfs: disabling flush barriers on hdc ReiserFS: hdc: Using r5 hash to sort names [...] AppArmor: AppArmor (version 2.0-19.43r6320) initialized audit(1183375207.877:2): AppArmor (version 2.0-19.43r6320) initialized audit(1183375220.582:3): audit_pid=2108 old=0 by auid=4294967295 NET: Registered protocol family 10 lo: Disabled Privacy Extensions IPv6 over IPv4 tunneling driver 8250: module not supported by Novell, setting U taint flag. Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled eth0: no IPv6 routers present _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users