[PVE-User] Incredible low fsync with HW raid: Intel RS2BL040 - SOLVED

Pongrácz István pongracz.istvan at gmail.com
Sat Jun 2 15:32:25 CEST 2012


----------------eredeti üzenet----------------- 
Feladó: "Pongrácz István" 
 
Címzett: pve-user at pve.proxmox.com 
Dátum: Sat, 2 Jun 2012 14:29:06 +0200 
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>
>
>Hi All,
>
>I have a system with PVE 1.8 with HW raid card (Intel RS2BL040), without BBU, 4 x 1.5Tbyte 
>hdd in RAID10
>
>I found that, the pveperf shows incredibeli low FSYNC, even 0.89.
>
>Guys, seriously, what the hack could happen to cause this incredibely low 
>measurement? Here are some test data and details about the system and settings.
>
>Does anybody meet this kind of situation?
>
>Any hints, documentation on the web are welcome.
>
>Thank you,
>
>István
>
> 
>
>
>
>Just for the record:
>
>When BBU is not exists, the default cache policy is no cache. So, forcing it to use even 
>BBU not present helped in that case the fsync value goes up to above 3000. There are still 
>lower fsync values and jumping speed values, but now these are much better than before.
>
>Summary: BBU is recommended using a system like this.
>
>Check the system with the command megacli -CfgDsply -aALL and grep the cache settings:
>
>Default Cache Policy: WriteBack, ReadAdaptive, Cached, Write Cache OK if Bad BBU
>Current Cache Policy: WriteBack, ReadAdaptive, Cached, Write Cache OK if Bad BBU
>
>pveperf 
>CPU BOGOMIPS: 40530.64
>REGEX/SECOND: 820487
>HD SIZE: 94.49 GB (/dev/mapper/pve-root)
>BUFFERED READS: 111.82 MB/sec
>AVERAGE SEEK TIME: 12.35 ms
>FSYNCS/SECOND: 3305.15
>DNS EXT: 46.68 ms
>DNS INT: 43.31 ms
>
>pveperf /var/lib/vz
>CPU BOGOMIPS: 40530.64
>REGEX/SECOND: 868581
>HD SIZE: 1663.48 GB (/dev/mapper/pve-data)
>BUFFERED READS: 86.59 MB/sec
>AVERAGE SEEK TIME: 14.09 ms
>FSYNCS/SECOND: 1711.62
>DNS EXT: 55.23 ms
>DNS INT: 43.82 ms
>
> 
>
> 
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