Linux crash with lin_tape driver
An IBM Spectrum Protect server running on RedHat 6.5 is configured with a Data Domain Virtual Tape Library, which emulates an IBM 3584 L32 library with LTO4 tape drives. The Linux system crashes with soft lockup errors with the lin_tape driver.
The /var/log/messages file shows the following error at the time of the crash :
BUG: soft lockup - CPU#3 stuck for 67s! [dsmserv:817]
The Linux dmesg command shows the following messages prior to the crash :
lin_tape: unable to reserve the device
lin_tape 7:0:0:6: reservation conflict
The lin_tape driver needs to be upgraded and persistent reserve needs to be disabled on the IBM Spectrum Protect server and the lin_tape driver.
Diagnosing the problem
Verify the level of the lin_tape driver with the following command :
rpm -qi lin_tape
In this case, the lin_tape driver level was 2.9.5.
Verify the library configuration with the following IBM Spectrum Protect server administrative command :
q library <library-name> F=D
In this case, the library was defined with "Reset Drives : Yes".
Resolving the problem
Upgrade the lin_tape driver to minimum level 126.96.36.199, which fixes known issues with soft lock errors on Linux. The lin_tape driver is available from the Fix Central site.
Disable persistent reserve with the library with the following IBM Spectrum Protect server administrative command :
update library <library-name> resetdrives=no
Follow the directions in the IBM Tape Device Drivers Installation and User's Guide to disable persistent reserve with the lin_tape driver.