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From: TooMeeK <toomeek_85@o2.pl>
To: KVM list <kvm@vger.kernel.org>
Subject: Virtual drives performance
Date: Wed, 07 Sep 2011 00:25:26 +0200	[thread overview]
Message-ID: <4E669DD6.5010805@o2.pl> (raw)

Hello,

I'm trying to set up a fast virtualized Samba file server. I'm using 
Debian Sqeeze 64 bit as hypervisor.
First, I created mirrored storage in hypervisor from one 600-gig 
partition (yes, that's correct - I have only one drive currently), details:
sudo mdadm --detail /dev/md3
/dev/md3:
         Version : 1.2
   Creation Time : Thu Jul 28 20:07:00 2011
      Raid Level : raid1
      Array Size : 664187352 (633.42 GiB 680.13 GB)
   Used Dev Size : 664187352 (633.42 GiB 680.13 GB)
    Raid Devices : 2
   Total Devices : 1
     Persistence : Superblock is persistent

     Update Time : Thu Jul 28 22:07:10 2011
           State : clean, degraded
  Active Devices : 1
Working Devices : 1
  Failed Devices : 0
   Spare Devices : 0

            Name : Server:3  (local to host Server)
            UUID : 87184170:2d9102b1:ca16a5d7:1f23fe2e
          Events : 3276

     Number   Major   Minor   RaidDevice State
        0       8       23        0      active sync   /dev/sdb7
        1       0        0        1      removed

Partition type is Linux RAID autodetect and this drive can do 80MB/s 
write and 100 MB/s read seq.

QEMU PC emulator version 0.12.5 (qemu-kvm-0.12.5)

Next, I've tried following combinations with virt-manager 0.8.4 (from 
XML of VM):
1.on Debian VM with virtio drivers for both storage and NIC:
<disk type='block' device='disk'>
<source dev='/dev/md3'/>
<target dev='vdb' bus='virtio'/>
partition type used in guest: EXT4
result: poor performance, 9-10MB/s sequentional copy via SMB
2.on Debian VM with virtio drivers:
<disk type='block' device='disk' cache='writeback'>
<source dev='/dev/md3'/>
<target dev='vdb' bus='virtio'/>
partition type used: EXT4
result: poor performance, 10-15MB/s sequentional copy via SMB
3.Direct attached partition to FreeBSD VM without virtio support (e1000 
NIC and SCSI disk):
<disk type='block' device='disk' cache='writeback'>
<source dev='/dev/md3'/>
<target dev='sdb' bus='scsi'/>
partition type used: ZFS
result: poor performance, 20-25MB/s sequentional copy via SMB
4.Direct attached whole physical disk to FreeBSD VM (/dev/sdc 2,5")
partition type used in VM: ZFS
good performance, 60MB/s sequentional copy via SMB

I find that way it's not possible to direct attach PARTITION from host 
to VM using virt-manager, this only works for whole device (like /dev/sdc).

Anyway, any storage advices for performance?


             reply	other threads:[~2011-09-06 22:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-06 22:25 TooMeeK [this message]
2011-09-07  5:50 ` Virtual drives performance martin f krafft
2011-09-07  7:52 ` Stefan Hajnoczi
2011-09-07  9:46 ` Asdo
2011-09-07 14:38 ` Virtbie

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