Start/notes.ini Parameters/NSF_DPOOL_LIMIT_SIZE

NSF_DPOOL_LIMIT_SIZE

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Parameter: NSF_DPOOL_LIMIT_SIZE
Short description: Maximum size of a DPool block in the 64-bit memory manager – affects handle limits and memory fragmentation with many loaded NSFs.

Profile

Parameter
NSF_DPOOL_LIMIT_SIZE
Category
Performance / Memory
Component
Server
Available since
12.0
Supported versions
12.0, 14.0, 14.5, 14.5.1
GUI equivalent
notes.ini only (no GUI)
Possible values
Bytes, power of two (e.g. 16777216 = 16 MB, 67108864 = 64 MB)

Description

DPools are the building blocks that the Domino memory manager uses to manage heap memory per database. On 64-bit servers with many open NSFs (mail hubs, hub clusters), the default value can lead to fragmentation and consequently to Insufficient Memory errors. Deliberately tuning NSF_DPOOL_LIMIT_SIZE increases the maximum block size and reduces allocation overhead.
The value should always be a power of two (16 / 32 / 64 MB are common).

Example configuration

NSF_DPOOL_LIMIT_SIZE=67108864

Notes & pitfalls

  • Useful only on 64-bit Domino.
  • Pairs with ConstrainedSHM, NSF_BUFFER_POOL_SIZE_MB, MEM_FillFreedMemory.
  • Incorrect values can significantly increase memory consumption – monitor via show stat memory.*.
  • Take a stats baseline before adjusting.
  • The change takes effect after a server restart.