On Mon, Apr 14, 2008 at 4:40 AM, Federico Sevilla III <[EMAIL PROTECTED]> wrote: > On Mon, 2008-04-14 at 00:48 -0700, Michael Tinsay wrote: > > Since you have 3 disks, why not go for RAID 5 to get striping accross > > the three disks? > > This is something I've been hoping to discuss with the other members of > this list. Assuming: > > 1. We'll be using Linux software RAID (md). > > 2. Everything else hardware including the hard drives are identical. > > Which will be faster? > > 1. RAID 1 with two drives > > 2. RAID 5 with three drives > > I'm noticing significant CPU time in IOWait and have a two-drive RAID 1 > setup, and am hoping to beef up the I/O subsystem with the only > realistic option being to add another drive and go into software RAID 5. > I don't know if this will make sense or not, though.
I guess raid 1 will win handily for general workloads. raid 5 on the other hand, you might even see some slight increase on read speed as md will not have to deal with parity. And oh, forget about write speed... have seen penalty of generally 10% to 30% degradation. The only time i have seen where raid 5 fly is on the EMC products like Clarions and DMX. Well, I guess 32Gb of oversize RAM cache on those beast does not hurt either... -- regards, Andre | http://www.varon.ca _________________________________________________ Philippine Linux Users' Group (PLUG) Mailing List http://lists.linux.org.ph/mailman/listinfo/plug Searchable Archives: http://archives.free.net.ph
