"scalar disk"?

[Jack Trachtman]

Recently released patch "VMS732_FIBRE_SCSI-V1100" includes the following line in its doc:

"5.2.1 Multipath Scalar Disk Hung in Mount Verification"

Just what is a "scalar disk"? What are non-"scalar disks" called? TIA

[Robert Brooks_1 · Accepted solution]

A few folks in VMS Engineering refer to non-shadowset devices as "scalar". In that vein, a "non-scalar" would be a shadow set member, although I don't think the term "non-scalar" was ever user. We tended to refer to them as "member devices", with the "DSA" device being called the "virtual unit, or
V. U. for short.

The context for that note in the patch kit is that multipath treats shadowing member devices slightly differently than non-member devices with respect to error recovery and mount verification, since shadowing has its own notion of mount verification. A member device is never in mount verification per se; only the virtual unit is in mount verification.

-- Rob


-- Rob

[Jack Trachtman]

Thanks Rob - good explanation