Open Directory and Memory Usage

[Brick]

A Mac technician recently made the following claim to a prospective client regarding an OS X server configuration:

“RAM is allocated upon conception of the ODM server, and, despite adding RAM to the server after the fact, it will not tally that RAM until it is reallocated. The only way to do this is to redo the OD setup from scratch.”

I’ve never heard this before and from everything I know, it sounds bogus to me. Being no great directory services guru, however, I’m hoping someone here can either confirm or annihilate the statement.

Thanks!

Gary Brick

[macmedicvic123]

Actually, that was me who made that (claim) recommendation to a Northern VA. law firm… and there was NO SMOKE, rather a lot of knowledge base…

It is the truth: Despite the fact that the physical RAM will show up in the system, the ODM is CACHING what it “Tallied” at conception and will not release that unless an administrator alters the DB_CACHE which lives in the OPENLDAP System/Server/var/DB/openldap/data/DB_CONFIG… I think that is the path… Altering that will probably destroy the server, so instead of doing something drastic like altering OD/LDAP cache, I would simply propose rebuilding the server in question. Besides, this server was promoted to ODM prior to Kerberizing and DNS activations… and it was poorly deployed… BTW: You should never promote to ODM without DNS and kerberos realm… single sign on… one must plan ahead and promote ODM very carefully, and be smart about it, especially when critical data is in the mix…

PS: The RAM/CACHE claim is clearly stated in the Peach-pit press OD Master training textbook if you need reference… or dig around Apple’s site.

Thanks,

[macmedicvic123]

Mac OS X Server: How to change the default BerkeleyDB cache size
In Mac OS X Server 10.3, the default BerkeleyDB cache size is 4 MB. In Mac OS X Server 10.4, the BerkeleyDB cache size depends on the amount of RAM installed on your computer when creating the LDAP master.

If your computer has 256 MB of RAM, the default BerkeleyDB cache size will be 16 MB. If your computer has more than 256 MB of RAM up to 512 MB, the cache size will be 32 MB. If your computer has more than 512 MB of RAM, the default cache size will be 64 MB.

Changing the cache size

If you’ve added more RAM to the server, you can manually increase the BerkeleyDB cache size, using the RAM to cache ratios described above as your guideline. This can also help improve LDAP performance.

To change the BerkeleyDB cache size in either Mac OS X Server version 10.3 or 10.4, open the file /var/db/openldap/openldap-data/DB_CONFIG in your preferred text editor, and edit the file by typing one of the corresponding values below:

For 4 MB: set_cachesize 0 4194304 1
For 16 MB: set_cachesize 0 16777216 1
For 32 MB: set_cachesize 0 33554432 1
For 64 MB: set_cachesize 0 67108864 1
Save the file, then restart the server to apply your change.

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