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Re: Scaling replicas

Alister Winfield wrote: 
On Sat, 2002-11-16 at 03:28, Quanah Gibson-Mount wrote:

Hello,

Has anyone seen any scaling issues with OpenLDAP -- i.e., if you have a single master, is there any sort of performance/replication slowdown noticed as you increase the number of replicas? Do people have a master with 10 replicas? 20? 30? 50 or more? Any issues noticed with a large number of replicas?

Thanks,
Quanah


--
Quanah Gibson-Mount
Senior Systems Administrator
ITSS/TSS/Computing Systems
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html



I suppose this should be reported but .... under load slurpd has in the
past lost updates for me. This has always happened when there are > ~10
slaves and higher than average update rate say >1 change a second.
Anyone else seen this ? Its very hard to replicate as its random and as
such I haven't ever found any hard proof as to why it happened. The most
important symptom was that the change never even got attempted according
to the logs on the affected slaves.

--
Alister Winfield - Easynet Systems Developer.


Yes, I've noticed this happening with OpenLDAP 2.0.* running under Solaris 2.7 . The problem is due to Solaris bug # 4472643 (fopen and fdopen fail in less than FOPEN_MAX or STREAM_MAX calls). I raised this with Sun some time ago - I got the reply that it might be fixed in Solaris 9. Our workaround is to take the load off the master and point clients at the replicas.

Dave
--
Dave Lewney
Principal Systems Programmer, Computing Service
University of Sussex, Brighton BN1 9QJ. Tel: 01273 678354 Fax: 01273 271956