[PVE-User] SSD Performance test

Marco Gabriel - inett GmbH mgabriel at inett.de
Tue Sep 17 12:21:12 CEST 2013


For SSDs you should set the I/O scheduler to "NOOP". Proxmox uses Deadline by default, which is good for spinning disks, but not for SSDs.

Examples (ssd is sdb): 

Get currently used scheduler:
    cat /sys/block/sdb/queue/scheduler
    noop anticipatory [deadline] cfq

Set scheduler:
    echo noop > /sys/block/sdb/queue/scheduler

best regards,
Marco


-----Urspr√ľngliche Nachricht-----
Von: pve-user-bounces at pve.proxmox.com [mailto:pve-user-bounces at pve.proxmox.com] Im Auftrag von Eneko Lacunza
Gesendet: Dienstag, 17. September 2013 12:12
An: pve-user at pve.proxmox.com
Betreff: [PVE-User] SSD Performance test

Hi all,

I'm doing some tests with a Intel SSD 320 300GB disk. This is a 3 Gbps disk with max ratings of R/W 270/205 MB/s and 39500/23000-400 IOPS.

The disk is attached to a Dell PERC H200 (LSI SAS2008) RAID controller, no raid, no logical volume, no cache and is mounted as "ext4 (rw,relatime,barrier=1,data=ordered)"

root at butroe:~# pveperf /srv/storage-local-ssd/
CPU BOGOMIPS:      36176.88
REGEX/SECOND:      761809
HD SIZE:           275.08 GB (/dev/sdc)
BUFFERED READS:    211.87 MB/sec
AVERAGE SEEK TIME: 0.23 ms
FSYNCS/SECOND:     1373.42
DNS EXT:           157.35 ms

I was expecting a better Fsync/second value, having seen on this list much better values with spinning disk RAIDs and taking into account this drive's IOPS rating.

What do you think? Maybe it's the lack of a controller write cache what is hurting the fsyncs and the value is good with a H200 controller?

Thanks
Eneko

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