Qemu slow disk throughput

I am doing some development for a UN community site, using Zope/Plone. I uses Qemu for hosting the guest OS for my development environment.

For 2 days, I keep wondering why Zope/Plone loads damn slow on the qemu machine eventhough I have allocated both cores of the processor, and 512RAM for it. 15 minutes simply to start up is really not desirable. I kept on investigating and guess what:

[root@unapcict ~]# /sbin/hdparm -t /dev/hda

Timing buffered disk reads: 18 MB in 3.03 seconds = 5.95 MB/sec

Just for a comparison, the host hdd's speed:

[root@Nobuyuki ~]# /sbin/hdparm -t /dev/sdc

Timing buffered disk reads: 174 MB in 3.01 seconds = 57.71 MB/sec

Darn.. So, thats what the reason. Dear lazywebs, anybody know how to improve the speed??.


aafr said…
maybe you should consider using other than qemu?
have u tried user mode linux?
Anonymous said…
VMs are (currently) always slower on I/O than the host system. However you might want to try something like VirtualBox to see whether its "disk" performance is higher...
Anonymous said…
I am running Xen 3.1.0 and my hdparm output result as below.

Below is Xen server: -
# hdparm -t /dev/sda

Timing buffered disk reads: 778 MB in 3.00 seconds = 259.28 MB/sec

Below is Xen guest: -
# hdparm -t /dev/xvda

Timing buffered disk reads: 438 MB in 3.00 seconds = 145.88 MB/sec

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