Re: Syncrepl vs. replication

[Dave Horsfall <daveh@ci.com.au>]

On Tue, 31 May 2005, Howard Chu wrote:

[ Central replication server ]

> This is generally a good solution, especially since the subtrees are 
> geographically distant. I'm not sure I understand what your top-level 
> referral server is accomplishing, but that's OK, not sure I need to 
> understand. ;)

It's just a poor man's "meta" backend (and a local directory, not a 
server; poor phrasing on my part):

suffix		"dc=au,dc=example,dc=com"
directory	/usr/local/openldap-data/au
...
suffix		"dc=sg,dc=example,dc=com"
directory	/usr/local/openldap-data/sg
...
suffix		"dc=example,dc=com"
directory	"/usr/local/openldap-data/master

A search of "dc=example,dc=com" will return a bunch of referrals:

ref: ldap://ldap.example.com/dc=au,dc=example,dc=com??sub
...
ref: ldap://ldap.example.com/dc=sg,dc=example,dc=com??sub

Our custom client will chase those (as will "ldapsearch" with the 
undocumented "-C" switch).

> The slurpd replication mechanism probably ran out of steam a long time 
> ago. I'm on the verge of completely replacing it with syncrepl in 2.3, 
> as slurpd itself is not viable in the dynamic config environment.

Noted; thanks.  After studying the documentation it looks like it will 
support what we want to do, without introducing any surprises.

> The usual disclaimers apply, but at the moment the features that existed 
> in 2.2 are far more stable in 2.3. The rough edges in 2.3 are all 
> related to new features; if you don't use them you'll get by just fine. 
> Syncrepl in 2.3 has been working very well.

Thanks again; I'll see if I can convince my boss to let me use a beta 
product in a production environment :-)  Especially if I'm going to be 
developing a new back-end...

> Back to the general layout, a possible alternative when accesses outside 
> the local suffix are infrequent, is to use back-ldap/back-meta with the 
> proxy cache for all the non-local suffixes. Just a thought. If you can't 
> easily characterize your non-local query traffic as a small set of fixed 
> query templates, it's probably too much trouble.

Yes, I've been thinking about that exact thing.

-- 
Dave Horsfall  DTM  VK2KFU  daveh@ci.com.au  Ph: +61 2 8425-5508 (d) -5500 (sw)
Corinthian Engineering, Level 1, 401 Pacific Hwy, Artarmon, NSW 2064, Australia