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Re: Why Use accesslog overlay?

--On Friday, March 20, 2009 3:08 PM -0400 Pete Giesin <pgiesin@hubcitymedia.com> wrote:

I am working on setting up OpenLDAP for a web project. I had originally
planned on using the accesslog overlay to track all access to the LDAP. I
have discovered that the use of this overlay has a tremendous impact on
performance.

I started out by auditing all operations. With this configuration I was
getting 40-50 reads/sec max. I then decided that I only needed to audit
writes. Making this change sent the reads through the roof, but the
writes were still only averaging 16-20 per second. I am in the process of
retesting the writes with no accesslog. My assumption is that the writes
per second will jump dramtically.

So I have to question what is the purpose of the accesslog overlay? Is it
really needed and if so is there are way to increase its performance. I
have to admit that I have not paid attention to the settings for the
accesslog backend. Do I need to tweak these settings just like I did for
my primary backend? If so what are the optimal settings for a write
intensive database?

It's a database like any other, so yes, it needs to be tuned appropriately to your work load. The accesslog overlay is most often used for things like delta-syncrepl replication. It can also be used to trigger actions based off what it writes out, as well.

--Quanah


--

Quanah Gibson-Mount
Principal Software Engineer
Zimbra, Inc
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