Re: [ovirt-users] Poor guest write speeds

Add this on to your dd command conv=sync And then report result. Its no surprise that your writes are slow in raid1 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> <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