Informix Error -173

Reasons / Common Causes

-173 is explicitly a generic wrapper, per the official text — logical-log backup failed, and the actual specific cause lives in the accompanying SQL API error text rather than in this code itself. Treat -173 as a signal to look elsewhere for the real diagnosis, not as the diagnosis.

1. Backup destination unavailable or out of space — the disk, tape, or remote target the log backup is writing to is full, offline, or otherwise unreachable.
2. Backup device or media issues, for physical tape or similar media — a drive fault, a bad tape, or a media-handling problem.
3. Network connectivity problems, if the backup target is remote — a dropped connection, a misconfigured network path, or a target host that's unreachable.
4. Permission issues on the backup destination — the process performing the backup lacking write access to the target location.
5. Continuous log backup configuration issues — a broken or misconfigured ongoing backup process failing partway through, related to the same log-backup discipline -121 discusses.

Solutions / Resolution

1. Check the accompanying SQL API error text first. Per the official guidance, this generic ISAM-level code wraps a more specific underlying error — the actual cause is described there, not in -173 alone.
2. Check backup destination availability and space (disk, tape, or remote target) — the most common practical cause behind a log backup failure.
3. Check backup device/media status if using physical tape or similar hardware.
4. For network-based backup targets, verify connectivity and configuration.
5. Review continuous log backup configuration for correctness if this is part of an ongoing automated process rather than a one-off manual backup attempt.
6. Once the underlying cause is identified from the SQL API error text, address it directly (free space, fix connectivity, replace media, correct permissions) and retry the backup.

Examples

Checking the associated error text first

-- Don't stop at "-173 ISAM error: An error has occurred during
-- logical log back up." — capture and read the accompanying SQL API
-- error text returned alongside it, which names the specific cause

A common practical cause: destination full

df -h /backup/logs
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdc1        20G   20G     0 100% /backup/logs

If the backup destination is full, that alone explains the failure — free space (or expand the destination) and retry.

Diagnostic Checks

1. Capture and review the accompanying SQL API error text — this is the actual diagnostic detail, per the official guidance.
2. Check backup destination space and availability:

   df -h /backup/logs
   

3. Check network connectivity if backing up to a remote target.
4. Review continuous log backup configuration and recent history for signs of an ongoing misconfiguration rather than a one-time failure.

Related Errors / Related Topics

• -100 — "ISAM error: duplicate value for a record with unique key." The other foundational ISAM-level error in this family.
• -121 — "ISAM error: cannot write log record." Related through the same log-management discipline — both point at the importance of a reliable, properly configured logical log backup process.

Always capture the accompanying SQL API error text — -173 by itself is intentionally generic, and that associated text is where the actual, specific cause is described.