Thanks Adam and to others for clearing up the misconception. George
On Mon, 4 Apr 2005 09:17:09 -0700, "Fox, Adam" Adam.Fox@netapp.com wrote:
This is absolutely false. I heard this strange misconception with RAID-4 too. (If you lose the parity disk, the whole thing falls down because it's all on 1 disk).
Here's a lab box to make you feel better.
Volume test (online, raid_dp) (block checksums) Plex /test/plex0 (online, normal, active) RAID group /test/plex0/rg0 (normal)
RAID Disk Device HA SHELF BAY CHAN Used (MB/blks) Phys(MB/blks) --------- ------ --------------- ---- --------------
dparity 0b.20 0b 1 4 FC:B 68000/13926400069536/142410400 parity 0b.21 0b 1 5 FC:B 68000/139264000 69536/142410400 data 0b.28 0b 1 12 FC:B 68000/139264000 69536/142410400
Spare disks (empty)
(note: No spares)
filer> disk fail -i 0b.20 filer> disk fail -i 0b.21
Now, here's sysconfig -r again:
Volume test (online, raid_dp, degraded) (block checksums) Plex /test/plex0 (online, normal, active) RAID group /test/plex0/rg0 (double degraded)
RAID Disk Device HA SHELF BAY CHAN Used (MB/blks) Phys(MB/blks) --------- ------ --------------- ---- --------------
dparity FAILED N/A 68000/139264000 parity FAILED N/A 68000/139264000 data 0b.28 0b 1 12 FC:B 68000/13926400069536/142410400
Spare disks (empty)
Broken disks
RAID Disk Device HA SHELF BAY CHAN Used (MB/blks) Phys (MB/blks)
admin failed 0b.20 0b 1 4 FC:B 68000/139264000 69536/142410400 admin failed 0b.21 0b 1 5 FC:B 68000/139264000 69536/142410400
Still running..but degraded.
-- Adam Fox adamfox@netapp.com
-----Original Message----- From: George Kahler [mailto:george@YorkU.CA] Sent: Monday, April 04, 2005 11:22 AM To: toasters@mathworks.com Subject: RAID-DP
At a recent NetApp presentation it was mention in passing that RAID-DP fails if a double disk failure happens to hit the two parity disk.
Is this true ?
George