[Fedora-directory-users] Advantages of using FDS vs OpenLDAP?
Kevin Myer
kevin_myer at iu13.org
Mon Jul 11 01:39:44 UTC 2005
Quoting Mike Jackson <mj at sci.fi>:
> Hi Pierangelo,
> The fact that LDAP directory servers are not intended to support a
> high frequency of write operations means that the term "write load
> balancer" is not the correct term to use when describing the benefits
> of multi-master versus single-master replication - unless you are
> arguing how to support systems architects who intentionally (or
> perhaps out of ignorance) use LDAP technology in an incorrect manner
> in their designs. The correct term to use in this context, IMO, is
> "highly available write operations".
I thought that more accurately describes it as well. And my approach would be
to have a "primary" master and a "secondary" master. Throw all your writes at
your primary master and if they all go through there, no need to worry about
consistency. In the event of a disaster, the secondary master is quite
capable
of taking the writes as well and keeping things running. This is almost akin
to your master/promotable slave concept, except the promotable slave is not
really a slave but a standby master. If you're concerned about load, throw in
a bunch of slaves that are read-only and point your read-only lookups at the
slaves, reserving your masters for applications that need write access.
End result - highly available write operations, that minimize consistency
issues. Highly available read operations. It requires intelligent
design of a
directory infrastructure, as you note - sometimes I think we expect
software to
design that too :)
Kevin
--
Kevin M. Myer
Senior Systems Administrator
Lancaster-Lebanon Intermediate Unit 13 http://www.iu13.org
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