Why do I see I/O errors on a RHEL system using devices from an active/passive storage array?
Issue
- I see I/O errors in my system logs from some of the devices on my storage array / SAN
- When I run LVM commands, I get I/O errors against some of the devices from my storage array
- Error message "
end_request: I/O error, dev sdb, sector 0
" found in messages file - Error message "
Buffer I/O error on device sdc, logical block 0
" found in messages file -
Additional messages about "
sense key: Not Ready
" may also be found:kernel: end_request: I/O error, dev sdc, sector 0 kernel: sd 0:0:0:3: Device not ready: <6>: Current: sense key: Not Ready kernel: Add. Sense: Logical unit not ready, manual intervention required
-
These
end_request: I/O error
messages are also logged on system console during boot process - On system with multipath configured, running LVM commands sometime hang or take long time and shows following error messages:
/dev/sde: read failed after 0 of 4096 at 0: Input/output error
Environment
- Red Hat Enterprise Linux(RHEL) 4
- Red Hat Enterprise Linux(RHEL) 5
- Red Hat Enterprise Linux(RHEL) 6
- Storage array operating in active/passive mode (see root cause for details)
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