Hello again.
So I have been doing some more testing just to be sure. I performed a
reboot of my Win7 ESXi guest VM between each running of the Parkdale HDD
speed test app, just to be absolutely sure the results were not a result
of caching and each time I get pretty consistent results: no less than
60 MByte/s Seq. Write and around the same for Seq. Read.
In oVirt, is there some tuning I am maybe missing? Is there a different
HDD type I should be selecting (or converting to)?
-Alan
On 27/07/2015 6:34 PM, Alan Murrell wrote:
Hello,
So a bit of an update, though I still have some additional testing to
do. I installed ESXi 5.5 on the same hardware (blew away my oVirt
install) and installed a Windows 7 VM, with same settings (2GB RAM, 1
single-core vCPU, 60GB thin-provisioned HDD)
The install of Windows itself was definitely *way* faster. I don't have
actual timings for real comparisons, but I can say with 100% certainty
that the install was faster. I would say it took at *least* half the
time to install as oVirt, though to be honest, I would have to say it
was maybe 1/3 of the time.
Once installed, I installed the VMware Guest Tools, then downloaded and
ran the "Parkdale" app with the same settings I ran it under the Windows
7 VM. The preliminary results are interesting.
The "Seq. Write" test comes up at around 65 MByte/s, which compares well
to the bare metal results I got previously. What is interesting (and
disappointing) is that the "Seq. Read" test indicates about 65MByte/s,
which is a *huge* decrease to what I was getting in the oVirt Win7 guest.
As I mentioned, still going to do some additional testing, but wanted to
let you know that -- initially, anyway -- the problem under oVirt does
not seem to be a hardware-related issue, but possibly something with the
virtio-SCSI?
For those who are running Windows VMs in production, what sort of
performance do you see? What type of virtual HDD are you running?
I will post back either later or some time tomorrow (Tue) with more
results.
-Alan
Quoting "Alan Murrell" <li...@murrell.ca>:
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
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