From: "DERUMIER, Alexandre via pve-devel" <pve-devel@lists.proxmox.com>
To: "pve-devel@lists.proxmox.com" <pve-devel@lists.proxmox.com>
Cc: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
Subject: [pve-devel] qcow2 internal snapshot: 4k write speed reduce to 100~200 iops on ssd ?
Date: Fri, 30 Aug 2024 16:01:44 +0000 [thread overview]
Message-ID: <mailman.477.1725033712.302.pve-devel@lists.proxmox.com> (raw)
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From: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
To: "pve-devel@lists.proxmox.com" <pve-devel@lists.proxmox.com>
Subject: qcow2 internal snapshot: 4k write speed reduce to 100~200 iops on ssd ?
Date: Fri, 30 Aug 2024 16:01:44 +0000
Message-ID: <fbddd72caac9d3474d63bdfcdb34bc515059ad70.camel@groupe-cyllene.com>
Hi,
I was doing tests with gfs2 && ocfs2,
and I have notice 4k randwrite iops going from 20000 iops to
100~200iops when a snapshot is present.
I thinked it was related to gfs2 && ocfs2 allocation,
but I can reproduce too with a simple qcow2 file on
a local ssd drive.
is it expected ?
(I don't have use qcow2 snapshot since 10year, so I really don't
remember performance).
Using external snapshot file, I'm around 10000iops.
test inside the vm:
fio --filename=/dev/sdX --ioengine=libaio --direct 1 --bs=4k --
rw=randwrite --numjobs=64
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next reply other threads:[~2024-08-30 16:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-30 16:01 DERUMIER, Alexandre via pve-devel [this message]
2024-09-11 9:11 ` Fiona Ebner
2024-09-19 13:50 ` DERUMIER, Alexandre via pve-devel
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