Start/notes.ini Parameters/Server_MinPossibleTransTime

Server_MinPossibleTransTime

Parameter: Server_MinPossibleTransTime
Short description: Lower bound (in microseconds) for the Server Availability Index (SAI) calculation by the Loadmon subsystem. On modern, fast servers the default lower bound yields a far too low SAI — typical HCL recommendation: 1500 to 2000. Often set together with Server_MaxPossibleTransTime=20000000.

Profile

Parameter
Server_MinPossibleTransTime
Category
Performance (Server Availability Index)
Component
Server (Loadmon / SAI)
Available since
8.5
Supported versions
9.0.1, 10.0, 11.0, 12.0, 14.0, 14.5, 14.5.1
GUI equivalent
notes.ini only (no GUI)
Possible values
Integer in microseconds (µs). Typical values: 1500–2000. Often combined with Server_MaxPossibleTransTime=20000000.

Description

The Server Availability Index (SAI) is a Domino-internal metric between 0 and 100 expressing how “available” a server appears to be under load. It is calculated by the Loadmon subsystem from statistic values, primarily from the typical NRPC transaction times of the server. On the console, show ai shows the current value.
Loadmon needs two anchor values:
  • Server_MinPossibleTransTime — how fast can an NRPC transaction be at best? (lower bound)
  • Server_MaxPossibleTransTime — how slow may it be at worst? (upper bound)
If measured transaction times are closer to Min, the server is “nimble” → high Availability Index. If they are closer to Max, it is “slow” → low index.
The problem on modern servers: Domino uses historical default values from the 2000s. Today's NVMe SSDs and fast CPUs deliver transactions in well below 1 ms. Loadmon compares this to the default min and gets a ratio that is practically always interpreted as “below what is theoretically possible” → SAI drops unrealistically into the low range (often 0 or single digits) even though the server is idle. Classic symptom: “Zero Availability Index and Slow Server Response for User”.
Solution (HCL forum + Daniel Nashed):
Server_MinPossibleTransTime=1500
Server_MaxPossibleTransTime=20000000
This shifts the reference frame so that modern hardware reaches realistic SAI values (50–100). Then measure under load via show ai and possibly fine-tune with Server_Transinfo_Range.

Example configuration

Standard recommendation for modern servers (Nashed blog):
Server_MinPossibleTransTime=1500
Server_MaxPossibleTransTime=20000000
Alternative from HCL Support tickets:
Server_MinPossibleTransTime=2000
Server_MaxPossibleTransTime=20000000
After changes:
# Stop the server, delete loadmon.ncf, start the server
show ai

Notes & pitfalls

  • Tuning order: 1) set both parameters, 2) stop the server, 3) delete loadmon.ncf from the data directory, 4) start the server, 5) observe show ai under load. Without deleting loadmon.ncf, Loadmon continues to compute with the old reference values.
  • Server_Transinfo_Range: after several show ai readings, the console provides a recommendation for Server_Transinfo_Range. Set this value additionally afterwards.
  • Mind the µs unit: 1500 means 1.5 ms — not 1.5 s. Typos here lead to chaotic SAI.
  • Check per server type: VM servers, containers, bare-metal and cloud instances deliver different fast min times. Adjust values per platform if necessary.
  • Cluster failover effect: SAI controls failover decisions in the cluster (Server_Availability_Threshold in the server document). A wrongly low SAI can trigger cluster-mate failover even though the server is healthy.
  • Server restart required — Loadmon initializes only at start.
  • Monitoring: show ai, show stat Server.AvailabilityIndex, show stat Server.Trans.AvgTime. In case of anomalies, check console.log and events4.nsf.
  • Source situation: HCL has no dedicated documentation page for this parameter; best practice is derived from HCL Support tickets, Daniel Nashed's blog (configuring-sai-loadmon-for-fast-servers) and the HCL Notes and Domino Community. For 14.5.1 still applicable unchanged.
  • Works on all supported platforms.

Sources

  • HCL Notes/Domino Community Forum – threads on Server_MinPossibleTransTime and Availability Index tuning
  • Note: HCL has no dedicated documentation page for this parameter on help.hcl-software.com/domino/. The recommendations are derived from HCL Support tickets, the community blog mentioned above, and forum threads — transparently disclosed here.