Basic IO benchmarks between zfs/lvm-thin/qcow2

Lucian

Well-Known Member
Nov 7, 2017
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Just ran these the other week, thought I'd share. I'll try to do some more proper ones on Linux, but before that happens here's some CrystalDiskMark ones on Windows 2019 (virtio-scsi).
The underlying storage is a single Samsung 850 PRO SSD.

I was pleasantly surprised by the QCOW2 performance, wish Proxmox focused on this some more, it should be trivial to have replication for this type of storage (rsync?).


2cores16ram32disk-qcow2.png

2cores16ram32disk-lvmthin.png

2cores16ram32disk-zfs.png
 
, wish Proxmox focused on this some more, it should be trivial to have replication for this type of storage (rsync?).

Yeah ... it is not. QCOW2 is not made for this, ZFS on the other hand is. Rsync is a very, very bad example for this, because it does not work well on very big files. The algorithm to detect differences can go rogue and it'll slow down terribly. We switched to stupid dd for that, which was in the end much more predicable.