How many disk failure can a 12 drive RAID 1+0 tolerate

[mjaveed]

Hello.

Please could anybody advice, how many disk failures can a 12 drive raid 1+0 tollerate.

Logical Drive: 1
Size: 1.6 TB
Fault Tolerance: RAID 1+0
Heads: 255
Sectors Per Track: 32
Cylinders: 65535
Strip Size: 256 KB
Full Stripe Size: 1536 KB
Status: Interim Recovery Mode
Array Accelerator: Enabled
Unique Identifier: 600508B1001CA1D048CD513F48AFA793
Disk Name: /dev/cciss/c1d0
Mount Points: None
OS Status: LOCKED
Logical Drive Label: A07020545001438021307A284AD5
Mirror Group 0:
physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 300 GB, OK)
physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 300 GB, OK)
physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SAS, 300 GB, OK)
physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SAS, 300 GB, OK)
physicaldrive 1I:1:5 (port 1I:box 1:bay 5, SAS, 300 GB, Predictive Failure)
physicaldrive 1I:1:6 (port 1I:box 1:bay 6, SAS, 300 GB, OK)
Mirror Group 1:
physicaldrive 1I:1:7 (port 1I:box 1:bay 7, SAS, 300 GB, Failed)
physicaldrive 1I:1:8 (port 1I:box 1:bay 8, SAS, 300 GB, OK)
physicaldrive 1I:1:9 (port 1I:box 1:bay 9, SAS, 300 GB, OK)
physicaldrive 1I:1:10 (port 1I:box 1:bay 10, SAS, 300 GB, OK)
physicaldrive 1I:1:11 (port 1I:box 1:bay 11, SAS, 300 GB, OK)
physicaldrive 1I:1:12 (port 1I:box 1:bay 12, SAS, 300 GB, OK)

[Torsten.]

In this case a complete mirror group, but if the next failed disk is the partner of the already failed disk, game is over.

So the answer is 1 disk (consider the worst case).