Rob Clark wrote: >> On July 14, 2008 7:49:58 PM -0500 Bob Friesenhahn >> <[EMAIL PROTECTED]> wrote: >> >>> With ZFS and modern CPUs, the parity calculation is >>> >> surely in the noise to the point of being unmeasurable. >> >> I would agree with that. The parity calculation has *never* been a >> factor in and of itself. The problem is having to read the rest of >> the stripe and then having to wait for a disk revolution before writing. >> -frank >> > > And this is where a HW RAID controller comes in. We hope it has a uP for > the calculations, full knowledge of the head positions, and a list of free > blocks -- then it simply chooses one of the drives that suit the criteria > for the RAID level used and writes immediately to the free block under > one of the heads. If only ... > > Maybe in a few years Sun will make a HW RAID controller using ZFS once > we all get the bugs out. With Flash updates this should work wonderfully. >
Given that a general-purpose CPU today tends to offer much better performance than embedded processors and the cost of developing special-purpose processors is high, how would you define the next generation "HW RAID" controller? -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
