Tape changer oddity

[Simon Hargrave]

I have an intriguing problem with a tape controller. It hangs off a fibre channel fabric, and is used by Veritas NetBackup. NetBackup has recently started balking about not being able to contact the device, and in the past only a reboot has aleviated this.

I've done some digging, and it's definately not a hardware problem. I can access the tape changer with "mc" using the "schgr" driver device file: -

crw------- 1 bin sys 231 0x0c0000 Feb 19 2003 c12t0d0

However when I try and access it through the "sctl" passthrough driver, as NetBackup requires: -

crw-r----- 1 root sys 203 0x0c0000 Feb 6 2004 c12t0l0

I get the error: -

ERROR: Device busy

This is with the command "mc -p -r S".

I can do this on other similar configured servers with both sctl and schgr so mc should work, just seems odd that I can access it from one driver, but not the other.

Any suggestions what I can do apart from reboot the server? Can I reset the sctl driver or something?

[RAC_1 · Accepted solution]

Bit confused with the post.
You have problems with sctl and schgr. Right?But mc works OK right??


Do you have lsof tool??? If yes, before checking the library with sctl and schgr commands, can you check if anything is using it??? lsof /dev/rac/cxtxdx.

Anil

[Bharat Katkar]

HI,
Did check the LIBRARY varibale.
It should be /dev/rac/c12t0d0

Hope that works.
Regards,

[Massimo Bianchi]

Hi,
I have such error with OB when any of the following conditions became true:

- there is a monitor instance that is accessing the device FIX -> disable the ems polling for the tapes and the schgr involved

- there are concurrent access to the device FIX -> try not to use the same device twice or more

Check also the values of the parameters st_san_safe and st_ats_enabled

Regards,
Massimo

[Simon Hargrave]

Thanks all. The problem was that I could use mc via one device but not the other.

The actual problem was solved with lsof. It revealed that an Omniback processes was using the device, killing it freed up the device.

Omniback hasn't actually been used here for over 12 months, but it seems some job is still trying to run! It will now be uninstalled!