On Tue, Apr 24, 2012 at 10:17 PM, John R Pierce pierce@hogranch.com wrote:
On 04/24/12 2:24 PM, Eero Volotinen wrote:
Anyway, with 18TB of raid 6 might cause performance problems .. raid 60 or raid 10 looks much better solution.
18TB of raid6 is only 8 3TB drives (6 + 2 parity).... thats not an unreasonable size for a raid6 set.
for the 81TB nearline storage boxes I built for a data archive application, I formatted each box (using a megaraid sas2 9260-8i card and 36 3TB SAS drives) as 3 x 11 x raid60, plus 3 hot spares, and then made one big XFS on that. Its working out quite nicely. I think 10 or 12 disks per raid5 or 6 is a good upper limit. rebuild time from a single failure was 12 hours, and from a double failure in the same raid plex, 18 hours.
-- john r pierce N 37, W 122 santa cruz ca mid-left coast
Actually in our case we've got 12 2TB drives - but still I think John's point stands.
Boris.