[ale] RAID5 chunksize?

[tslane at attbi.com]

what kind of controller? (AMI, IBM, etc.)

I believe more cache on the RAID card (assume you're not doing soft 5 if
performance is critical) will buy you a lot more performance for random writes
than chunk size.  FWIW, I've had good luck w/AMI MegaRAID.  IBM's (formerly
Mylex) used to be (much) faster but were extremely unstable on Linux although
eith or both of these may have changed since last summer when I was going
through this.

my advice is to get the controller with the biggest cache you can afford.

what say ye all?
> 
> 
> Ok, say I'm building a 4 disk raid5 array.  Performance is going to be
> critical as this system is going to be very IO intensive.  We had to go
> RAID5 though due to filesystem requirements.
> 
> According to the manufacturer the disks have:
> 
>   8Meg DataBuffer
>   10K RPM Rotational speed
>   SCSI Ultra 160
> 
> (Drive is:
> http://www.fel.fujitsu.com/home/product.asp?L=en&PID=248&INFO=fsp)
> 
> What is the ideal Chunksize?  
> 
> Also it's going to have a lot of pretty decent sized files (100Meg or 
> so average) so I was going to make it an ext3 with -T largefile and -M 1.
> 
> Any other thoughts on how to lay down the disks/filesystem on this
> bugger?
> 
> Robert
> 
> 
> 
> 
> 
> :wq!
> ---------------------------------------------------------------------------
> Robert L. Harris                     | PGP Key ID: FC96D405
>                                
> DISCLAIMER:
>       These are MY OPINIONS ALONE.  I speak for no-one else.
> FYI:
>  perl -e 'print $i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10);'
> 
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