[SOLVED] Poor performance 5.1

[Deni74]

Hi,
VM: W2k8r2 Enterprise, MS SQL Server 2012r2

Spoiler: VM:

balloon: 0
boot: cdn
bootdisk: ide0
sockets: 1
cores: 8
cpu: host
ide0: local:999/vm-999-disk-1.qcow2,format=qcow2,size=160G (no cache)
ide1: local:999/vm-999-disk-2.qcow2,format=qcow2,size=80G (no cache)
memory: 20480
name: ms
net1: e1000=FE:0A:30:95:A4:E2,bridge=vmbr0
numa: 0
ostype: win7
smbios1: uuid=f96a5fb1-3917-4f0c-96af-8829f9ed1038

HOST: AMD FX-8350, 32 Gb, 2Tb+2Tb Sata3 WD Black (not lvm-thin)

No problems with version 3.4. After installation 5.1 very poor performance. Processor (2-4%), but slow response to any action. For example ms sql database restore: 3.4 ~ 1h min. 5.1 ~ 3 h.

 

[Deni74]

After converting from qcow2 to raw, database restore ~ 30 min. mhmm.....
raw faster than qcow, yes of course. with 3.4 there was no such difference. It is very strange.

 

[mbaldini]

Have you tried with virtio or virtio-scsi drivers instead of IDE (very slow driver).
What is the file system of the proxmox host?

 

[Deni74]

ext4 host's file system. normal performance with ide raw disk (see above) with or without virtio drivers. problem with qcow2. qcow2 or raw, with virtio or not, in proxmox 3.4 there was no such difference in performance. IDE (very slow driver) - yes, but I'm most interested in the question, why so with 5.1

 

[micush]

I saw similar results in my Linux VMs. Slow qcow2 performance. Switched everything to raw a while back and have been happy since. I miss the flexibility of qcow2, but I'll take the performance improvement over the flexibility.

 

[Deni74]

I saw similar results in my Linux VMs. Slow qcow2 performance. Switched everything to raw a while back and have been happy since. I miss the flexibility of qcow2, but I'll take the performance improvement over the flexibility.

Yes, you are right. Raw... be it so, be it so.

 

[mbaldini]

You could use LVM-thin or ZFS to have snapshot and other features of qcow2

 

[micush]

I could, but simpler is better. i've got everything mounted over 40G via NFS. No additional RAM requirements, no zpool knobs to turn, direct access to the disk files, etc.

 

[Deni74]

So, why qcow2 performance in 3.4 is normal and in 5.1 so poor... very poor (with same conditions, settings and equipment) ?

 

[mailinglists]

I haven't read whole thread, but if you are using local filesystem like ext3 or 4 to store your raw or qcow2 images, it might be due to barriers being enabled by default in latest PMs version 4 and up. I think PM4 uses ext4 which has barriers enabled, PM v 3 uses ext3 which has barriers disabled. Try disabling barriers, but do read uppon what does that mean for your data in case of power loss (possible loss of data).

Add nobarrier option via fstab, then reboot and check via /proc/mounts then test the speed again. Let me know, if I guessed correctly.

 

[Deni74]

Yes! Absolutely forgot about it, because so long time used 3.x version. Thank you.