[PVE-User] poor HDD performance

[Alain Péan]

Le 23/05/2013 14:05, Patryk Benderz a écrit :
> [cut]
>> That said I think it is not a matter of drivers (modules version) but
>> a matter of default settings that can be controlled while loading the
>> module (man modprobe).
> Hi Luca,
> going after your advice i tried to look for differences in
> configuration. I took my another x3250 M2 server running
> pve-manager/1.9/6567, which is very similar. In fact lspci claims it has
> identical SAS RAID controller:
> proxmox218:~# lspci
> [...]
> 01:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS (rev 02)
> [...]
>
> ...and to my surprise ancient 1.9 PVE is performing very well on this
> controller, so slowness must be related to some software somehow:
> proxmox218:~# pveperf
> CPU BOGOMIPS:      23999.29
> REGEX/SECOND:      981650
> HD SIZE:           33.22 GB (/dev/mapper/pve-root)
> BUFFERED READS:    113.74 MB/sec
> AVERAGE SEEK TIME: 4.09 ms
> FSYNCS/SECOND:     66.27
> DNS EXT:           2009.57 ms
> DNS INT:           2006.31 ms (localdomain)
>
>
> proxmox218:/etc# lsmod|grep mpt*
> mptsas                 28948  2
> mptscsih               16360  1 mptsas
> mptbase                48206  2 mptsas,mptscsih
> scsi_transport_sas     19673  1 mptsas
>
> As seen above, both machines use same modules, so at the moment I am
> looking for proper way of inserting mpt* modules, and what are possible
> options I can pass while loading them. I will also try to use modules
> provided by LSI for RedHat.
>
>> My 2cents.
> quite important 2 cents :)
>

But nevertheless, 'FSYNCS/SECOND: 66.27 ' is very slow. To be usable (if 
they were no VM accessing the disk...), you need at least several 
hundred as FSYNC/SECOND. My first test Proxmox server with a 10k SAS 
drive and also a cheap LSI controller, was around 500.

On a production server (Dell PE R620, Perc H710 as Raid controller, 8 
drives NearLine SAS 7200 rpm in Raid 10), with some VMs currently 
running (but light VMs), I have :
# pveperf
CPU BOGOMIPS:      110388.00
REGEX/SECOND:      1138469
HD SIZE:           94.49 GB (/dev/mapper/pve-root)
BUFFERED READS:    436.00 MB/sec
AVERAGE SEEK TIME: 6.67 ms
FSYNCS/SECOND:     3169.06
DNS EXT:           58.90 ms
DNS INT:           41.61 ms

So FSYNCS/SECOND around 2000 or above is what you usually see for a 
serious host server.

(It is with PVE 3.0 RC2)

Alain

-- 
Administrateur Système/Réseau
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