[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] qcow2: slow internal snapshot creation
From: |
Alexandre DERUMIER |
Subject: |
Re: [Qemu-devel] qcow2: slow internal snapshot creation |
Date: |
Fri, 23 Nov 2012 16:53:00 +0100 (CET) |
>>Can you post more details about your benchmark setup so that this can be
>>reproduced? And does it reproduce with local files as well or only using
>>NFS?
Sure, I have redone tests, here the results:
(note that my netapp san have a nvram journal, so directio are as fast than
buffered io)
preallocated vs non preallocated have a ratio of 5/1 for local, and 10/1 for
nfs.
directio bench
---------------
fio --filename=/dev/vdb --direct=1 -rw=randwrite --bs=4K --size=5G
--iodepth=100 --group-reporting --name=file1 --ioengine=libaio
buffered io bench
------------------
fio --filename=/dev/vdb --direct=1 -rw=randwrite --bs=4K --size=5G
--iodepth=100 --group-reporting --name=file1 --ioengine=libaio
results
-------
local raw file
---------------
cache=none, directio, 9000 iops
cache=none, buffered io, 10000 iops
local qcow2 preallocated
--------------------------
cache=none, directio, 8000 iops
cache=none, buffered io, 9000 iops
local qcow2 non preallocated
-----------------------------
cache=none, directio, 1400 iops
cache=none, buffered io, 2000 iops
nfs rawfile (netapp with nvram journal)
----------------------------------------
cache=none, directio, 15000 iops
cache=none, buffered io, 15000 iops
nfs qcow2 preallocated (netapp with nvram journal)
-------------------
cache=none, directio, 12000 iops
cache=none, buffered io, 12000 iops
nfs qcow2 non preallocated (netapp with nvram journal)
-----------------------------------------------------
cache=none, directio, 1500 iops
cache=none, buffered io, 1500 iops
Alexandre D e rumier
Ingénieur Systèmes et Réseaux
Fixe : 03 20 68 88 85
Fax : 03 20 68 90 88
45 Bvd du Général Leclerc 59100 Roubaix
12 rue Marivaux 75002 Paris
----- Mail original -----
De: "Kevin Wolf" <address@hidden>
À: "Alexandre DERUMIER" <address@hidden>
Cc: "Dietmar Maurer" <address@hidden>, address@hidden
Envoyé: Vendredi 23 Novembre 2012 15:58:09
Objet: Re: [Qemu-devel] qcow2: slow internal snapshot creation
Am 23.11.2012 15:17, schrieb Alexandre DERUMIER:
>>> Preallocation doesn't matter much these days.
>
> I have done benchmark through nfs on a netapp san, (with directio),
>
> I got 300 iops without preallocation, and 6000 iops with preallocation ....
This doesn't sound right, even for writethrough modes.
Can you post more details about your benchmark setup so that this can be
reproduced? And does it reproduce with local files as well or only using
NFS?
Kevin
Re: [Qemu-devel] qcow2: slow internal snapshot creation, Kevin Wolf, 2012/11/23