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Re: slow cn=config changes; Re: Correct procedure to backup LDAP?

Howard Chu wrote:
I should note that for this specific example, you can also set readonly mode using cn=monitor, which has no particular impact on the thread pool, so it should take effect immediately.
back-config should be used for __persistent__ changes to configuration; back-monitor for __transient__, __volatile__ changes to configuration. For this purpose, back-monitor was designed to allow some limited modifications to the deamon's status (log level, readOnly and so; suggestions for more useful ones are welcome). One drawback of the back-monitor approach to your problem is that readOnly takes effect immediately, but it does not affect already running write operations. It might be safe to wait a while, or use again the back-monitor interface to see if any write operation is pending (this might not be that easy if the server contains more than one database). To do that, look at write operations under "cn=Operations,cn=Monitor" and see if the "monitorOpInitiated" is larger than "monitorOpCompleted".

I realize there might be need for running operations monitoring, possibly as children of active connections, which also indicates what backend is being affected. On a side note: "readOnly" does not guarantee that no write operations occur to a database, because internal writes could still occur as a consequence of other operations; consider, for example, password policy related entry updates performed by slapo-ppolicy(5), or dynamic object updates performed by slapo-dds(5).


Ing. Pierangelo Masarati
OpenLDAP Core Team

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