MTTIN499A Dev 07C1 COMMAND REJECT errors when trying to use non-silo STK 9840 tape drives at an alternate site

Products

• Mainframe VM Product Manager
• VM:Manager Suite for Linux on Mainframe
• VM:Manager Suite for z/VM
• VM SUITE
• VM:Tape for z/VM

Issue/Introduction

We are receiving the following errors when trying to use non-silo STK 9840 tape drives at an alternate site:

 VMTATT191I ATTACH 07C1 TO VMTAPE AS 0310
 VMTTIN499A Dev 07C1 COMMAND REJECT
 VMTTIN135S Permanent I/O error occurred on '7C1'; virtual address 0310.
 VMTTIN136I Sense is 804800C0 20312041 209FFF00 00000000 0000001A 2B000090
 VMTTIN137I CSW is 000960E8 0C00000; CCW is 9FA13349 2000001

We are experiencing the above errors when trying to use non-silo STK 9840 tape drives. They are online and can be used without VM:Tape, but when VM:Tape attaches one of the drives to mount a tape, we get Permanent I/O errors.

This is the same type of drive we use in production at our home site, but here at this site the errors occur. There is no MIM or drive sharing, we are just trying to use the 9840 external to the silo.

What could be causing the COMMAND REJECT?

 

Resolution

The CCW that is failing is a LOAD_DISPLAY which should never fail and it is getting a COMMAND REJECT.

The problem is that the control block information indicates the drive is ACL capable, so VM:Tape sets the "ACL bit" on for these drives in the LoadDisplay CCW being sent for a SCRATCH mount.

This results in the COMMAND REJECT because STK 9840s doe not support ACLs.

To prevent this from occurring, issue the following command to force ACL support OFF:

 VMTAPE DEBUG SUPPORT ACL OFF

This only happened because the silo drives were accessed as NONARM.