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

[Martin Maurer]

Hi,

> -----Original Message-----
> From: pve-user-bounces at pve.proxmox.com [mailto:pve-user-
> bounces at pve.proxmox.com] On Behalf Of Bill Carlson
> Sent: Dienstag, 09. November 2010 16:17
> To: pve-user
> Subject: [PVE-User] Windows guest disk I/O write slow
> 
> 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

[Martin Maurer] 
Looks like you do not installed some packages (especially pve-qemu-kvm is missing)

> aptitude update
> aptitude install proxmox-ve-2.6.32

And post your pveversion -v again.

> 
> 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
> 

[Martin Maurer] 
Slow fsyncs, means you do not have a raid controller with write-back. 
Or you got a single hard drive with cache disabled.
FSYNCS/SECOND should be at least 1000, with raid controller much higher.

Br, martin


> 
> 
> 
> --
> Bill Carlson
> 
> 
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