On 7/6/2011 3:05 AM, Christoph Hellwig wrote: > On Wed, Jul 06, 2011 at 05:22:21PM +1000, Dave Chinner wrote: >> Unless you have a good sized chunk of BBWC in front of your disks, >> in which case internal logs are just as fast. In fact, internal logs >> can are often faster in this case because an internal log on a 12 >> disk RAID6 array can sink a whole log more bandwidth than an external >> log on a 2-disk RAID0 mirror..... >> >> At least, that's what my hardware tells me. ;) > > Sure, a nice BBWC setup will give you good results. But it's generally > much more expensive than a simple setup with a raid5 or 6 and a mirror for > the log device. If you're talking consumer grade gear, well, sure, as there is no such thing as a consumer hardware RAID card. In the world of branded OEM 'enterprise' gear, you can get a BBWC RAID card solution for little more than two drives. Are most XFS admins running consumer or enterprise grade gear? LSI 9260-4i w/512MB BBWC = $485 USD Intel RES2SV24024P expander = $280 USD Total = $765 USD 2 HP 146GB 10kRPM SAS drives = $520 USD. I threw in the expander as this LSI card is thoroughly limited with only 4 ports. It's also cheaper going this route than buying the sister card with 8 ports, yet with the same performance, and 12 more total ports. -- Stan _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
