The dmesg command will usually show information about hardware errors.
An example from a spinning disk:
sd 0:0:10:0: [sdi] Unhandled sense code
sd 0:0:10:0: [sdi] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 0:0:10:0: [sdi] Sense Key : Medium Error [current]
Info fld=0x6fc72
You didn't mention which version you're upgrading to, but generally you
shouldn't add or
remove nodes while the nodes your cluster is not all on on the same version. So
if you're
going to add nodes, you should do that before you upgrade the first node, or
after you have
upgraded all of them.
