On Tuesday, 27 March 2001 at 0:05:03 -0800, Alfred Perlstein wrote:
> * Greg Lehey <[EMAIL PROTECTED]> [010326 23:47] wrote:
>> On Tuesday, 20 March 2001 at 11:11:44 -0600, Michael C . Wu wrote:
>>> [Lengthy email, bear with me please, it is quite interesting.
>>> This box averages 30.0 load with no problems.]
>>>
>>> <snip>
>>>
>>> Average file size is about 4K. /home/bbsusers* is on a vinum
>>> stripe'd volume with 3 Ultra160 9G 10000RPM drives on sym0 at stripe
>>> size 256K, Greg: I know this should be a prime number,
>>
>> No, there's no requirement for it to be a prime number. The only
>> problem is that with 32 MB cylinder groups and a power of two stripe
>> size and subdisk count, you end up with all the superblocks on one
>> subdisk, which is a performance issue. Choose the stripe size so that
>> the superblocks are roughly evenly distributed.
>>
>>> can we safely use <150K stripe sizes?
>>
>> Safely, yes. But as somebody else has observed, you are probably disk
>> I/O bound. Reducing the stripe size will tend to increase the disk
>> load, though probably not very much if your files are all 4 kB. I'd
>> go for something like 273 kB stripes.
>
> Do you think it'd be worth it to have vinum carp about what may
> be a non optimal stripe size?
>
> "Warning N is probably a bad idea for a stripe size, see docs"
Only if it can recognize the fact correctly.
Greg
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