Memory management in Domino 8

If you are running Domino on systems with more then 2GB of RAM at some point you have probably had to tune the amount of memory available to Domino (especially if you are running on AIX).  There are a number of ways to do this most commonly by implementing either PercentAvailSysResources, or ConstrainedSHM/ContrainedSHMSizeMB in your notes.ini.  This controls how Domino calculates the size of the UBM (unified buffer manager).  If the UBM grows to large Domino is prone to crash.   In previous versions of Domino the UBM was allocated by taking a percent of the memory available to Domino, in Domino 8 by default the UBM is set to 512 MB, which according to testing is the most efficient setting, though NSF_BUFFER_POOL_SIZE_MB can still be used to increase the UBM if desired, but it is not recommended.   Keep this in mind when upgrading servers and strongly consider removing any of the previously mentioned ini parameters from the notes.ini and let Domino 8 manage the memory with it;s default setting. I won’t be upgrading my production servers to 8 until next year, but am considering setting my 6.5.x servers to NSF_BUFFER_POOL_SIZE_MB=512 and removing ConstrainedSHM which should allow my 6.5.x servers to allocate memory the same way Domino 8 will by default. Technote 1268988 New default limit on UBM size in Domino 8

One Response to Memory management in Domino 8
  1. Chris Whisonant
    November 8, 2007 | 4:17 pm

    That should be a fairly good test. Although, 6.5.x and 8.0 would have different ways of handling the memory in general. So this could give you skewed results.

    How is your buffer pool currently?

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