Re: [zfs-discuss] install opensolaris on raidz

2008-07-19 Thread Ross 
Err... I think you guys are talking cross purposes here.  Either I'm missing 
the point completely, or are you not aware that the Thumper2 includes a flash 
storage slot so the OS doesn't use any of the 48 disks any more?

No, it's not mirrored, but Richard was trying to point out that it's likely Sun 
felt the benefit of mirroring that CF drive would be minimal.
 
 
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Re: [zfs-discuss] Raid-Z with N^2+1 disks

2008-07-19 Thread Rob Clark 
 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.
 
 
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