[Beowulf] RAID storage: Vendor vs. parts

[Alvin Oga]

hi ya steve

On Tue, 22 Feb 2005, Steve Cousins wrote:

> That's what I'm shooting for. Anybody have good luck with volumes greater
> than 2 TB with Linux?  I think LSI SCSI cards are needed (?) and the 2.6
> Kernel is needed with CONFIG_LBD=y.  Any hints or notes about doing this
> would be greatly appreciated.  Google has not been much of a friend on
> this unfortunatlely. I'm guessing I'd run into NFS limits too.

for files/volumes over 2TB ... it's a question of libs, apps and kernel 
	everything has to work ... which is not always the case

	i don't play much with 2.6 kernels other than on suse-9.x boxes
  
> Also, am I being overly cautious about having a spare RAID controller on
> hand?  How frequent do RAID controllers go bad compared to disks, power
> supplies and fan modules?  I'd guess that it would be very infrequent.

it's always better to have spare parts ... ( part of my requirement ) if
they expect the systems to be available 24x7 ... 

	- more importantly, how long can they wait, when silly inexpensive
	things die, before it gets replaced

	- dead fans is $2.oo - $15 each to keep the disks cool

	- power supply is $50 range ... but if one bought n+1 powersupply
	than its supposed to not be an issue anymore, but you will need to
	have its replacement handy

	- raid controllers should NOT die, nor cpu, mem, mb, nic, etc
	and it's not cheap to have these items floating around as spare
	parts

	- ethernet cables will go funky if random people have access
	to the patch panels ... ( keep the fingers away )

	- ups will go bonkers too

	- what failure mode can one protect against and what will happen
	if "it" dies 

	- best protection against downtime for users is to have an
	warm-swap server which is updated a hourly or daily ... 
	( my preference - 2nd identical or bigger-disk capacity system )

> Looking back at my own experience I think I've had to return one out of 15
> in the last eight years, and that was bad as soon as I bought it.

seems too high of a return rate ?? 1 out of 15 ??

> If this is too off-topic let me know and I'll move it elsewhere.

ditto here 

24x7x365 uptime compute environment is fun/frustrating stuff on tight
budgets

c ya
alvin