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Re: slow or inconsistent syncrepl

Amol Kulkarni wrote:
Dear Quanah,

Thanks a lot for these 2 pointers. I'll check out the 2.4.30 version.
We had used delta syncrepl earlier but our accesslog size used to grow
suddenly sometimes and the disk used to get full crashing/hanging the ldap
service itself on the provider. But at that time we had kept the max age for
the accesslog to be 7 days. I'll reduce it and give it a try again.

Also it would be helpful if you can throw some light on :

2. On a really busy ldap server, can replication slow down drastically? i.e
does the read operations affect the replication in any way?

Syncrepl executes as an LDAP Search operation, so of course it competes for server resources with other Search activity on the server.

4. We are currently having about 60 consumers - is this too much ? What can be
the max numbers of consumers ?

That depends entirely on the speed of your server and network. If you're seeing that replication speed is inconsistent, you probably should reduce the load on the provider. A simple approach in your scenario would be to just point the 10 consumers on the fast LAN at the provider, and configure these consumers to act as providers for your WAN nodes (i.e., cascaded replication).

5. Sometimes we urgently need some particular node to be present on the
consumer - for which we cannot wait - in that case we get ldif of that node
from provider and do ldapadd on the consumer ( mirrormode is ON on the
consumers ). Is this safe and correct or could it cause some side effects ? Is
there a better way to handle it?

If you have configured distinct serverIDs for each consumer, this might work. Otherwise, no, not safe, not correct.

Fix your configuration layout, or fix your apps. If your apps can't wait then they are mis-designed; there is no such thing as instantaneous propagation of information in the real world.

Thanks and Regards,
Amol Kulkarni.

----- Original Message -----

From: Quanah Gibson-Mount

Sent: 03/09/12 11:57 PM

To: Amol Kulkarni, openldap-technical@openldap.org

Subject: Re: slow or inconsistent syncrepl

--On Friday, March 09, 2012 2:20 PM +0100 Amol Kulkarni
<amolkulkarni@gmx.com>  wrote:

>  I have a following openldap setup with syncrepl :
>   - openldap version 2.4.23

This is your #1 issue.

>   - 1 provider and about 10 consumers in lan and 50 consumers on wan

This is your #2 issue.

Upgrade to a stable release.  Use delta-syncrepl, which uses significantly
less bandwidth than syncrepl.



Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
Zimbra ::  the leader in open source messaging and collaboration

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  CTO, Symas Corp.           http://www.symas.com
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  Chief Architect, OpenLDAP  http://www.openldap.org/project/