bad performance with ext4

zerokawa

New Member
Oct 10, 2012
19
0
1
Hello,
i create a new virtual machine.
Diskwrite with 1MB/s.
See screenshot with bad speed.

bad_performance.jpg

My image was before ntfs partition. So I reached up to 50MB / s when installing Windows.
In the version 2.3 but no vm starts with ntfs.
Poor performance with ext4.

Someone has an idea

System partition is a single disk
My image partition is ext4 with three hard drives in a software raid five.

Is the cause the software raid?
 
Last edited:
software raid is not recommended and not known to be fast.

you can do a simple benchmark on the host (but only when the host is idle).

Code:
pveperf

and post the config for your VM:

Code:
qm config 304

as soon as your windows box is installed, run a benchmark inside (CrystalDiskMark).

see my screenshot.
Screen_Intall-Win7.jpg


the installation of a Win7 takes about 8 minutes on this host (locally stored qcow2 files, ext4)
(Fast Adaptec Raid Controller (6805) but 5 years old hard disks)
 
Last edited:
I change the partition to qcow2 is better with performance.

pveperf
CPU BOGOMIPS: 39782.22
REGEX/SECOND: 886754
HD SIZE: 94.49 GB (/dev/mapper/pve-root)
BUFFERED READS: 88.42 MB/sec
AVERAGE SEEK TIME: 13.00 ms
FSYNCS/SECOND: 1276.05
DNS EXT: 35.95 ms
DNS INT: 34.36 ms


bad performance with vmdk

qm config 302
balloon: 512
bootdisk: sata0
cores: 6
memory: 1024
name: CL1
net0: e1000=A6:A3:40:89:59:5B,bridge=vmbr0
ostype: win7
sata0: local4:302/vm-302-disk-1.vmdk,size=32G
sata1: local2:iso/Original_Win7_pro_x64.iso,media=cdrom,size=3191550K
sockets: 1

I broke the installation with vmdk.


A screenshot of cristal mark disk and partition with qcow2.

CDM.jpg


My virtual machines run again.

There is a command to convert an existing vm config with vmdk to qcow2?
 
Last edited:

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!