[PVE-User] Windows guest disk I/O write slow

[Bill Carlson]

Hello,

Got a strange issue with Windows guests, disk write speed is horrible.

Used Microsoft's sqlio for tests, read speed is fine:

sqlio v1.5.SG
1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  7032.73
MBs/sec:    13.73


Write speed however:

sqlio v1.5.SG
1 thread writing for 30 secs to file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:    30.70
MBs/sec:     0.05

I've verified by simple copies this is correct.

Where to start looking?


Guest setup:
ide2: none,media=cdrom
bootdisk: ide0
ostype: wxp
memory: 1536
sockets: 1
onboot: 0
cores: 1
boot: cad
freeze: 0
cpuunits: 1000
acpi: 1
kvm: 1
ide0: virtualmachines:103/vm-103-disk-1.raw


Windows XP

PVE version:
pve-manager/1.6/5261
root at base1:/etc/qemu-server# pveversion -v
pve-manager: 1.6-5 (pve-manager/1.6/5261)
running kernel: 2.6.32-4-pve
pve-kernel-2.6.32-4-pve: 2.6.32-25
pve-kernel-2.6.24-9-pve: 2.6.24-18
qemu-server: 1.1-22
pve-firmware: 1.0-9
libpve-storage-perl: 1.0-14
vncterm: 0.9-2
vzctl: 3.0.24-1pve4
vzdump: 1.2-8
vzprocps: 2.0.11-1dso2
vzquota: 3.0.11-1

pveperf:
CPU BOGOMIPS:      51071.48
REGEX/SECOND:      891403
HD SIZE:           0.99 GB (/dev/mapper/system-root)
BUFFERED READS:    52.69 MB/sec
AVERAGE SEEK TIME: 6.75 ms
FSYNCS/SECOND:     113.04
DNS EXT:           93.32 ms




-- 
Bill Carlson