Hi DownSouth, and welcome back! Thanks for helping me sort this out...
"RAID 0+1" is not RAID at all. Though I am not sure what "0+1" means, as that is not a RAID term, it sounds like they are using Mirroring, which is very expensive and also slow, as all writes are duplicated
Just to clarify, 'RAID 0+1' was the term he used to describe the mirroring and striping that their SAN device uses. While the mirroring may be expensive for writes, their application using the Filer was extremely read intensive.
It does rebuild the contents of the failed drive to the new drive (which was sitting ready for use) using RAID parity techniques. Sys admin controls the amount of CPU resource allowed to be used in the rebuild. It can be as low as 10% or as high as 90%.
But when requests come in for the data stored on the drive being rebuilt, doesn't the CPU have to calculate (using parity) what was supposed to be at that location? So, if you have users hammering on this NAS device (which he says they were), this could slow response and performance times, could it not?
FWIW, he was very impressed with the NetApp box and said that it was an excellent product for its target market. But they apparently needed some things that the NAS couldn't offer.
BWDIK!
Justin, NTAP long.... |
