On Wed, 2005-06-22 at 13:54 -0700, Dan Stromberg wrote: > On Wed, 2005-06-22 at 12:33 -0700, Mike Hardy wrote: > > > I'm very interested in the relative SW raid / HW raid performance. I > > have both in service (two raid 5 sets are actually the same size with > > the same number of components) and see roughly the same as you mention. > > One difference that I see is that HW raid should generate fewer > > interrupts and lower bus traffic. > > In the early days of RAID, people always used to say that for speed, you > had to get a hardware RAID controller instead of doing software RAID. > > However, I saw an interesting comment on a local linux user group > mailing list recently. That comment was to the effect that hardware > RAID controllers tend to have no where near the horsepower of a modern > desktop CPU - so the claim was (I've not verified this!) that using > software RAID would be much faster. > > I'm thinking that if you can do software RAID with a dedicated box > that's doing nothing but RAID and a little network, then yes, that > likely would be faster than some scaled-down hardware RAID controller - > but it would also likely cost more, be less likely to have good hot > swap, and so on. This is very true. Especially with 64bit machines. The software RAID is much faster and efficient. However with servers that are using a lot of CPU resources it can become a bottleneck. Our inhouse application is proven faster with hardware RAID than with software RAID. Mainly due to the 100% CPU utilization. It being able to offload the IO to the MegaRAID card helps. I can't wait to test it with the new 320-2E. The CPU is twice as fast as the 320-2X we use now. Brad Dameron SeaTab Software www.seatab.com - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
