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Re: commit: ldap/doc/man/man5 slapd-bdb.5
<quote who="Howard Chu">
> Gavin Henry wrote:
>> <quote who="hyc@OpenLDAP.org">
>>> Update of /repo/OpenLDAP/pkg/ldap/doc/man/man5
>>>
>>> Modified Files:
>>> slapd-bdb.5 1.36 -> 1.37
>>>
>>> Log Message:
>>> Add dncachesize
>>
>> A new one for the tuning section. Will add soon.
>>
>> Also, in the e-mail titled "Maximum size of the database."
>>
>> - What is the maximum size of the database that OpenLDAP can support ?
>> - What is the maxmum number of dns it can hold ?
>>
>> For the Tuning section and General info in out Guide, how does someone
>> calculate the above?
>>
>> I'm interested as you said, "For a machine with 4GB of RAM I think it
>> will
>> max out at around 1-2 million DNs."
>>
>> What is the rule of thumb for above?
>
> I probably misspoke. See
> http://www.openldap.org/lists/openldap-software/200611/msg00051.html
> instead.
>
> A back-bdb EntryInfo node on a 32 bit machine is around 64 bytes, not
> including
> the length of the RDN stored in the node. (For back-hdb the node is about
> 20
> bytes larger). Assuming an average RDN length of 20-30 bytes, that makes
> each
> node around 100 bytes total. So 1 million DNs would consume about 100MB,
> and 10
> million DNs would consume about 1GB.
>
> On a 32 bit machine a user process typically can only address 2GB of
> memory,
> though you can sometimes tweak that up to 3GB.
>
> Of course if your average RDN length is shorter, then you can cache more
> within
> those constraints. Likewise, if you're running a 64 bit OS, your process
> address space has much higher limits, far higher than anyone is likely to
> bump
> into.
Thanks. I'll make sure this gets discussed inthe correct section of the
Admin guide.
Gavin.