Nope, haven't tried that. At the time I was testing this I didn't even think of trying it. I'm not even sure I'd heard of RAID 50 at the time... :) I basically had an old MegaRAID 4xx series card in a dual PPro 200 and a stack of 6 9 gig hard drives. Spare parts. And even though the RAID 1+0 was relatively much faster on this hardware, the Dual P IV 2800 with a pair of 15k USCSI drives and a much later model MegaRAID at it for lunch with a single mirror set, and was plenty fast for our use at the time, so I never really had call to test it in production. But it definitely made our test server, the aforementioned PPro200 machine, more livable. On Tue, 2006-07-18 at 14:43, Ron Peacetree wrote: > Have you done any experiments implementing RAID 50 this way (HBA does RAID 5, OS does RAID 0)? If so, what were the results? > > Ron > > -----Original Message----- > >From: Scott Marlowe <smarlowe@xxxxxxxxxxxxxxxxx> > >Sent: Jul 18, 2006 3:37 PM > >To: Alex Turner <armtuk@xxxxxxxxx> > >Cc: Luke Lonergan <llonergan@xxxxxxxxxxxxx>, Mikael Carneholm <Mikael.Carneholm@xxxxxxxxxxxxxxx>, Ron Peacetree <rjpeace@xxxxxxxxxxxxx>, pgsql-performance@xxxxxxxxxxxxxx > >Subject: Re: [PERFORM] RAID stripe size question > > > >On Tue, 2006-07-18 at 14:27, Alex Turner wrote: > >> This is a great testament to the fact that very often software RAID > >> will seriously outperform hardware RAID because the OS guys who > >> implemented it took the time to do it right, as compared with some > >> controller manufacturers who seem to think it's okay to provided > >> sub-standard performance. > >> > >> Based on the bonnie++ numbers comming back from your array, I would > >> also encourage you to evaluate software RAID, as you might see > >> significantly better performance as a result. RAID 10 is also a good > >> candidate as it's not so heavy on the cache and CPU as RAID 5. > > > >Also, consider testing a mix, where your hardware RAID controller does > >the mirroring and the OS stripes ((R)AID 0) over the top of it. I've > >gotten good performance from mediocre hardware cards doing this. It has > >the advantage of still being able to use the battery backed cache and > >its instant fsync while not relying on some cards that have issues > >layering RAID layers one atop the other. >
