Informix Error -645: Cannot reserve volume.

Reasons / Common Causes

-645 fires when a RESERVE statement's attempt to reserve an optical volume fails — per the official guidance, the specific reason is carried by an accompanying error from the optical subsystem itself, in the -7000 to -7199 range, a distinct numeric range from the ordinary SQL error codes covered in this set.

1. An underlying optical-subsystem-level failure (media unavailable, jukebox/library hardware issue, the specific volume already reserved elsewhere), per the official guidance's pointer to the accompanying -7000..-7199 error.
2. A valid RESERVE statement syntactically (having already passed the -641/-642/-643 checks on family/volume argument types and validity) failing at the physical/subsystem level instead.

Solutions / Resolution

1. Check the accompanying optical-subsystem error (in the -7000 to -7199 range), per the official guidance — that error carries the specific reason the reservation failed.
2. Confirm the requested family/volume identify an actual, available optical volume, since a valid-looking RESERVE statement can still fail if the physical volume itself isn't available.
3. Engage whoever administers the Optical Subsystem hardware (jukebox/library) if the accompanying -7000..-7199 error points to a hardware/media-availability condition.

Examples

Checking the accompanying optical-subsystem error

-- A -645 failure is accompanied by a second error in the -7000..-7199
-- range -- that error identifies the specific subsystem-level reason
-- (this errata set doesn't currently cover that separate numeric range).

Diagnostic Checks

1. Identify and look up the accompanying -7000..-7199 optical-subsystem error code — that's the documented path to the specific cause, per the official guidance.

Related Errors / Related Topics

• -641 — "Cannot reserve/release family on non-optical media." A related, earlier-stage RESERVE/RELEASE validation error.
• -642 — "Family name must be a character string." A related earlier-stage validation error.
• -643 — "Volume must be a number." A related earlier-stage validation error.
• -646 — "Cannot release volume." The mirror-image failure, on the RELEASE side.

The specific cause lives in a separate accompanying error (-7000..-7199), not in -645 itself — look that one up for the actual reason.