Start/notes.ini Parameters/Console_Log_Mirror

Console_Log_Mirror

Parameter: Console_Log_Mirror
Short description: Enables console log mirroring: Domino starts an additional server thread that writes every console output in parallel to numbered mirror files (console1.log, console2.log, …), providing a real log history instead of just circular overwriting.

Profile

Parameter
Console_Log_Mirror
Component
Server
Category
Logging / Debug
Available since
Domino 8.x; currently documented in HCL Domino 10.0.1–14.5.1
Value format
0 (off, default) or 1 (on)
Effect
Creates mirror files console1.log…console999.log in the IBM_TECHNICAL_SUPPORT directory

Description

Without mirroring, Domino writes its console output only to the single file IBM_TECHNICAL_SUPPORT/console.log and overwrites it circularly as soon as Console_Log_Max_Kbytes is reached. The history is then lost.
With Console_Log_Mirror=1, an additional server thread "Console Log Mirror Task" is started, which copies each entry from console.log in parallel to a mirror file. As soon as console.log reaches its limit and wraps, the mirror task closes the current backup file and creates a new one with a sequential number: console1.log, console2.log, ..., up to a maximum of console999.log. The smallest free number is used (e.g. if only console10.log exists, the next one created is console9.log, then console11.log).

Implicit effects

According to HCL Domino 10.0.1 Documentation ("Using console log mirroring"):
  • Mirroring automatically enables circular logging in the main file.
  • The default for Console_Log_Max_Kbytes is set to 100,000 KB (100 MB); the maximum is 1,000,000 KB (1 GB).
  • If Console_Log_Max_Kbytes is not explicitly set, Domino behaves as if Console_Log_Max_Kbytes=100000 were set — the value is, however, not written back to notes.ini.
  • Keystrokes on the server console are also mirrored into the logs (e.g. backspaces are visible).

Behavior on server restart

  • Default: when the Domino server starts, all console<N>.log files are deleted and only the current console.log plus a new console1.log are created anew.
  • With Retain_Mirror_Logs=1 additionally set, the existing mirror files are preserved.

Failure case

If the mirror task fails or falls behind by more than 3 seconds (read/write errors, I/O pressure), Domino automatically disables mirroring and logs to console.log:
Console Log Mirror Task has been disabled
Mirroring then remains disabled until the next server restart.

Examples

Enable mirroring with default limit (100 MB per file):
Console_Log_Enabled=1
Console_Log_Mirror=1
Mirroring with explicit 200 MB per mirror file and retained backups:
Console_Log_Enabled=1
Console_Log_Mirror=1
Console_Log_Max_Kbytes=200000
Retain_Mirror_Logs=1

Notes

  • Disk space — with mirroring, up to 999 × Console_Log_Max_Kbytes files can accumulate. At 100 MB per file, that is theoretically ∼100 GB. Regularly check the IBM_TECHNICAL_SUPPORT directory for growth, or omit Retain_Mirror_Logs.
  • Linux tip — on Linux systems it is advisable to place IBM_TECHNICAL_SUPPORT (or via debug_outfile only console.log) on a dedicated/tmpfs volume to relieve the database disk from logging I/O.
  • Change takes effect only after restart — the effect of Console_Log_Mirror only applies after a server restart.
  • Companion parameters — Console_Log_Enabled, Console_Log_Max_Kbytes, Retain_Mirror_Logs, debug_outfile.

Sources (HCL Product Documentation)