Hello,
I am running oVirt 3.5 on a single server (hosted engine). I have
two Western Digital WD20EZRX drives in a hardware RAID1
configuration. My storage is actually on the single server, but I
am attaching to it via NFS.
I created a Windows 7 guest, and I am finding its write speeds to be
horrible. It is a VirtIO-SCSI drive and the guest additions are
installed.
The installation of the OS took way longer than bare metal or even
VMware. When I ran Windows updates, it again took a *lot* longer
than on bar metal or on VMware.
The read speeds seem to be fine. The guest is responsive when I
click on programs and they open about as fast as bare metal or
VMware.
I downloaded and ran "Parkdale" HDD tester and ran a test with the
following settings:
- File size: 4000
- Block Size: 1 MByte
The results are as follows:
- Seq. Write Speed: 10.7 MByte/sec (Random Q32D: )
- Seq. Read Speed: 237.3 MByte/sec (Random Q32D: )
I ran another test, but this time changing the "Block Size" to "64
kByte [Windows Default]". Results are as follows:
- Seq. Write Speed: 10.7 MByte/sec (Random Q32D: )
- Seq. Read Speed: 237.3 MByte/sec (Random Q32D: )
On the host, running '
dd bs=1M count=256 if=/dev/zero of=test
conv=fdatasync' on my data mount via NFS rsuled in the
following:
256+0 records in
256+0 records out
268435456 bytes (268 MB) copied, 3.59431 s, 74.7 MB/s
I got this
<https://romanrm.net/dd-benchmark> and measures the
write speed of a disk. As you can see, it is significantly higher
than what I am getting in the Windows guest VM.
Running that same "dd" test on an Ubuntu guest VM gives me 24MB/s.
Any ideas why I have such poor write performance? Is this normal
with oVirt guests? Any ideas on what I might be able to do to
improve them? I don't expect to get close to the "bare metal"
results, but maybe something in the 40-60 MB/s range would be nice.
Thanks, in advance, for your help and advice.
-Alan