Re: [ovirt-users] Poor guest write speeds

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" <lists(a)murrell.ca&gt;: > 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 > > _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users