SAS Raid - mfi driver

Fredrik Widlund fredrik.widlund at
Tue Oct 31 12:31:29 UTC 2006

256MB cache, no BBU. Tried a lot of different combinations of settings.

fbsd 6.2pre writes 220MB/s with raid-0

If I boot windows server 2003 instead, it writes at around 180MB/s with
raid-5 (same configs).

With fbsd6.2pre, I get the "best" performance with BadBBU/direct
io/disabled cache and 8 drives, maybe around 50 MB/s, however I get a
zig-zag performance pattern, with the adapter running at 500% (gstat)
utilization one second, then down to 0% for maybe 3 seconds, back, etc.


Ivan Voras wrote:
> Fredrik Widlund wrote:
>> Ivan Voras wrote:
>>> Several:
>>> - are there cache differences between the controllers (amount of
>>> memory, cache policy)?
>> Default settings on both.
> Maybe you should check what the defaults are :) Especially the amount
> of memory and is there a battery to back the cache.
>>> - how does writing directly to the device (bypassing file system)
>>> compare?
>> Drives are four seagate 7200.10 400GB in a Raid-5 configuration.
>> [/mnt/test (/dev/mfid0p1 mounted)]
>> read: 200MB/s
>> write: 15MB/s
>> [/dev/mfid0p1]
>> read: 200MB/s
>> write: 8MB/s
>> [/dev/mfid0]
>> read: 200MB/s
>> write: 10MB/s
> This is bad :( The difference between p0 and raw device might indicate
> a stripe size misalignment, but the values are too low in any case.
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