Linux on IBM Z - dasd devices fail to attach, accompanied with messages "Setting the DASD online with discipline DIAG failed with rc=-95"
Issue
DASD storage on IBM Z series running Red Hat Enterprise Linux with use_diag=1 setting fails with boot up messages like:
0.0.0300: A 64-bit DIAG call failed
dasd: 0.0.0300 Setting the DASD online with discipline DIAG failed with rc=-95
Environment
- Red Hat Enterprise Linux 7 on IBM Z (mainframe)
- kernel 3.10.0-1160.el7.s390x -- detected on this kernel version, but the issue exists on versions pre-dating kernel-3.10.0-1160.10.1.el7
- DASD storage and driver presence
- use_diag flag is set (use_diag=1)
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