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Re: Speeding up BDB question


On Mon, 4 Apr 2011, Quanah Gibson-Mount wrote:

--On April 4, 2011 3:12:40 PM -0400 "Cannady, Mike" <mike.cannady@htcinc.net> wrote:

I have a situation where I need to delete a major branch of my DIT and
reload it with a new ldif file on live systems.  My current
configuration is a two node multi-master running on Red Hat Enterprise
5.4 with openldap 2.22 and BDB 4.8.26.

I strongly advise using a later version of OpenLDAP for a variety of reasons. That aside, why not use a shared memory key for the BDB backing cache instead of putting it on disk?

propably because most people and packagers just default to berkeley db file
based caching and the sysv shared memory caching is largely unknown.

Perhaps this sould be featured more in the documentaion.

Finally, RAM will always be faster than disk. If your database is properly configured via the threads, entry cachesize, the idl cachesize, the checkpoint frequency, and the BDB DB_CONFIG configuration for locks, lockers, and DB cachesize, then there's probably not much more you can do.

Of course, you don't provide any data that lets us know whether or not the settings you showed are valid. I.e., you don't state the number of DNs in the database, or the size of the database, or any of your stats from the BDB database.

I have seen performance get exponentially worse on linux with the linux
fsync changes that came somewhere after the 2.6.18 kernels.  Performance
on linux has never been fully restored with later kernels.


Christian Kratzer                      CK Software GmbH
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