Compromised Fault Tolerance; Recovering From Fault Tolerance Failures - HP Smart Array -UX 11i v2 Support Manual

For example, in the following sautil <device_file> command output excerpt, spare disk
1I:1:10 is being substituted for failed disk 1I:1:11, which is why the logical drive is in the
RECOVERING state.
---- LOGICAL DRIVE SUMMARY ---------------------------------------------------
# RAID
0 1+0
---- SAS/SATA DEVICE SUMMARY -------------------------------------------------
Location Ct Enc Bay
internal 1I
N/A 1I
internal 1I
internal 1I
internal 2I
internal 2I
internal 2I
internal 2I
---- SAS/SATA ENCLOSURE SUMMARY ----------------------------------------------
Location Ct
internal 1I
internal 2I
---- LOGICAL DRIVE 0 ---------------------------------------------------------
Logical Drive Device File........... c5t0d0
Fault Tolerance Mode................ RAID 1+0 (Disk Mirroring)
Logical Drive Size.................. 34700 MB
Logical Drive Status................ OK
# of Participating Physical Disks... 2
Participating Physical Disk(s)...... Ct:Enc:Bay:WWID
Participating Spare Disk(s)......... Ct:Enc:Bay:WWID
Stripe Size......................... 128 KB
Logical Drive Cache Status.......... cache enabled
Configuration Signature............. 0xA00148CC
Media Exchange Detected?............ no
For more information about the sautil command, see

Compromised fault tolerance

Compromised fault tolerance commonly occurs when more physical disks have failed than the fault
tolerance method can support. When fault tolerance fails, the logical volume also fails and
unrecoverable disk error messages are returned to the host. Data loss is likely to occur.
For example, suppose one drive fails in an array configured with RAID 5 fault tolerance while
another drive in the same array is still being rebuilt. If the array has no online spare, the logical
drive fails.
Compromised fault tolerance can also be caused by non disk problems, such as temporary power
loss to a storage system or a faulty cable. In such cases, the physical disks do not need to be
replaced. However, data can still be lost, especially if the system is busy when the problem occurs.

Recovering from fault tolerance failures

When fault tolerance has been compromised, inserting replacement disks does not improve the
condition of the logical drive. Instead, if your screen displays unrecoverable error messages, follow
these steps to recover data:
1. Power off the server, and then power it back on.
In some cases, a marginal drive will work long enough to enable you to make copies of
important files.
2. Make copies of important data if possible.
104 Physical disk installation and replacement
Size Status
34700 MB RECOVERING
WWID
1 12 0x500000e01117c732
1 11 0x500000e01115c352
1 10 0x5000c5000032b839
1 9 0x5000c5000030b0c5
1 16 0x500000e011213482
1 15 0x5000c500002084c9
1 14 0x5000c5000030b9c9
1 13 0x500000e01118a7a2
Enc Expander_count Bay_count
1 0 4
1 0 4
1I:1:12:0x500000e01117c732
1I:1:11:0x500000e01115c352 <-- NOT RESPONDING
1I:1:10:0x5000c5000032b839 <-- activated for 1I:1:11:0x500000e01115c352
Type Capacity Status
DISK 36.4 GB OK
N/A N/A FAILED
DISK 36.4 GB SPARE (activated)
DISK 36.4 GB UNASSIGNED
DISK 36.4 GB UNASSIGNED
DISK 73.4 GB UNASSIGNED
DISK 36.4 GB UNASSIGNED
DISK 36.4 GB UNASSIGNED
SEP_count
1
1
"The sautil command" (page 60).