[Beowulf] real hard drive failures

[Michael Will]

On Tuesday 25 January 2005 01:42 pm, Alvin Oga wrote:
> > I'm moving to a 3 drive raid5 setup on each node (drives are cheap, down time 
> > is not) and considering changing to Seagate SATA drives anyone care to offer 
> > opinions or more anecdotes?  :-)
> 
> == using 4 drive raid is better ... but is NOT the solution ==
> 
> 	- configuring raid is NOT cheap ...
Depends on what controller you use. 3ware escalade can be scripted with tw_cli.

> 	- fixing raid is expensive time ... (due to mirroring and syncing)
Lower performance while reconstructing and degraded, but back to normal
after the replacing drive has been updated.

> 	- if downtime is important, and should be avoidable, than raid
> 	is the worst thing, since it's 4x slower to bring back up than
> 	a single disk failure
You are talking about double disk failure that brings down the raid5?
 
> 	- raid will NOT prevent your downtime, as that raid box
> 	will have to be shutdown sooner or later 
> 	( shutting down sooner ( asap )  prevents data loss )
Hot-swappable drive bays should be the standard nowadays, and do not
require shutdown of the server.
 
Michael
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