[ale] RAID5 chunksize?

[Drag0n]

	I have had lots of experience with the IBM ServRaid cards, The biggest
trick is matching the bios/firmware revision and the driver revision. If
those dont match, then the driver will kernel panic under heavy loads.
They have many functionalities that other Raid controllers only dream
of, but for that extra your going to pay more. One feature is Hardware
clustering, with 2 systems and an external array between the two, you
can have a fully automatic failover on DB's. or file servers. a lot
depends on what your willing to pay for. The driver/configuration ISO
you download from their web site is a mini linux distribution with a
flash application, and X windows based configuration tool.

Drag0n
dragon at atlantacon.org

tslane at attbi.com wrote:
> 
> 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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> > Ale at ale.org
> > http://www.ale.org/mailman/listinfo/ale
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