From: Steve Benson <steve@in...> - 2002-08-21 17:29:38
Recently I started looking at UML to host some small production services to
reduce the number of physical servers we have. UML seems to work very well.
The only thing is that the disk I/O performance doesn't seem so great. I
used dbench to benchmark disk I/O for the UML virtual machine and host.
dbench reported a consistent throughput of around 20MB/sec running on the
host system, and around 6-7 MB/sec running within a UML machine.
The host system is a dual PII 400 with 384MB RAM and an ATA 6.4 GB disk (one
of the relatively newer western digitals of that size).
The host filesystems are ext3 and a stock redhat 7.3 2.4.18 kernel. The UML
kernel is the stock 2.4.18-36 kernel (from the UML website). The UML's
filesystems are ext2 filesystem images sitting in the hosts's filesystem.
One thing I tried was running a UML that booted off a raw partition on
another disk connected to the host that contained another installation...
ie, "ubd0=/dev/hdc2". This didn't really yield much of a performance
increase. I plan on trying other filesystems within the UML today to see if
Does anyone have any advice on increasing the I/O performance of UMLs?