"Alex Turner" <armtuk@xxxxxxxxx> writes: > Given the fact that most SATA drives have only an 8MB cache, and your RAID > controller should have at least 64MB, I would argue that the system with the > RAID controller should always be faster. If it's not, you're getting > short-changed somewhere, which is typical on linux, because the drivers just > aren't there for a great many controllers that are out there. Alternatively Linux is using the 1-4 gigabytes of cache available to it effectively enough that the 64 megabytes of mostly duplicated cache just isn't especially helpful... I never understood why disk caches on the order of megabytes are exciting. Why should disk manufacturers be any better about cache management than OS authors? In the case of RAID 5 this could actually work against you since the RAID controller can _only_ use its cache to find parity blocks when writing. Software raid can use all of the OS's disk cache to that end. -- greg
