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eMail server cluster

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cyruspy at gmail

Sep 14, 2009, 9:30 AM

Post #1 of 12 (1870 views)
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eMail server cluster

Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
would like to know if anybody has done something similar. My main
doubt is about using ClusterIP or a loadbalancer with LVS in front of
the two nodes. LVS would imply a third machine and i'm not sure how
the origin of the outgoing connections (IP address) is handled by
ClusterIP.

Any comments?.

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
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timo.schoeler at riscworks

Sep 14, 2009, 9:36 AM

Post #2 of 12 (1811 views)
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Re: eMail server cluster [In reply to]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

thus Ciro Iriarte spake:
> Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
> would like to know if anybody has done something similar. My main
> doubt is about using ClusterIP or a loadbalancer with LVS in front of
> the two nodes. LVS would imply a third machine and i'm not sure how
> the origin of the outgoing connections (IP address) is handled by
> ClusterIP.
>
> Any comments?.

Hi,

I don't really see the need of a third machine (thusly possibly
introducing a SPOF) into this setup, as two machines (running postfix,
cyrus, etc.) may hold the shared virtual IP themselves.

- From my experience, however, cyrus is not the best solution to be run in
a cluster. Maybe dovecot is worth a look?

(I write this being a very long year cyrus user myself, but planning to
migrate to dovecot for various reasons, not only the 'cluster issue'.)

HTH,

Timo

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Version: GnuPG v1.4.5 (GNU/Linux)
Comment: Using GnuPG with CentOS - http://enigmail.mozdev.org/

iD8DBQFKrnEEO/2mgkVVV7kRAtEcAJ9Mh0rLUeOfXB098TRUKIdPKFRjnwCeN0a6
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misch at multinet

Sep 14, 2009, 9:47 AM

Post #3 of 12 (1815 views)
Permalink

Re: eMail server cluster [In reply to]

Am Montag, 14. September 2009 18:30:26 schrieb Ciro Iriarte:
> Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
> would like to know if anybody has done something similar. My main
> doubt is about using ClusterIP or a loadbalancer with LVS in front of
> the two nodes. LVS would imply a third machine and i'm not sure how
> the origin of the outgoing connections (IP address) is handled by
> ClusterIP.
>
> Any comments?.

Well, LVS does not nescessarly need a third machine. See:
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-
HOWTO.localnode.html#two_box_lvs

I would use two machines and put the following software on the machines:
- Mail Application: potfix, cyrus
- Load Balancer: LVS, ldirectord
- pacmaker for the high availability.

then you have high availabiliy, load balancing and nearly unlimited
scalability. ldirectord integrates very nicely into a pacemaker cluster.

Please feel free to contact me for further question.

Greetings,

--
Dr. Michael Schwartzkopff
MultiNET Services GmbH
Addresse: Bretonischer Ring 7; 85630 Grasbrunn; Germany
Tel: +49 - 89 - 45 69 11 0
Fax: +49 - 89 - 45 69 11 21
mob: +49 - 174 - 343 28 75

mail: misch [at] multinet
web: www.multinet.de

Sitz der Gesellschaft: 85630 Grasbrunn
Registergericht: Amtsgericht München HRB 114375
Geschäftsführer: Günter Jurgeneit, Hubert Martens

---

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Skype: misch42
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cyruspy at gmail

Sep 14, 2009, 9:54 AM

Post #4 of 12 (1816 views)
Permalink

Re: eMail server cluster [In reply to]

2009/9/14 Timo Schoeler <timo.schoeler [at] riscworks>:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> thus Ciro Iriarte spake:
>> Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
>> would like to know if anybody has done something similar. My main
>> doubt is about using ClusterIP or a loadbalancer with LVS in front of
>> the two nodes. LVS would imply a third machine and i'm not sure how
>> the origin of the outgoing connections (IP address) is handled by
>> ClusterIP.
>>
>> Any comments?.
>
> Hi,
>
> I don't really see the need of a third machine (thusly possibly
> introducing a SPOF) into this setup, as two machines (running postfix,
> cyrus, etc.) may hold the shared virtual IP themselves.
>
> - From my experience, however, cyrus is not the best solution to be run in
> a cluster. Maybe dovecot is worth a look?
>
> (I write this being a very long year cyrus user myself, but planning to
> migrate to dovecot for various reasons, not only the 'cluster issue'.)
>
> HTH,
>
> Timo
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.5 (GNU/Linux)
> Comment: Using GnuPG with CentOS - http://enigmail.mozdev.org/
>
> iD8DBQFKrnEEO/2mgkVVV7kRAtEcAJ9Mh0rLUeOfXB098TRUKIdPKFRjnwCeN0a6
> WEkHhTMamyB21hfd8Vr3/+4=
> =CUX5
> -----END PGP SIGNATURE-----

Can you elaborate on you cyrus + cluster experience? (maybe out of
band if it's OT), OCFS2 1.4.0 supports shared writeable mmap now,
which seems all that is needed to run cyrus on top of it.

Regards,

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

cyruspy at gmail

Sep 14, 2009, 10:04 AM

Post #5 of 12 (1804 views)
Permalink

Re: eMail server cluster [In reply to]

2009/9/14 Michael Schwartzkopff <misch [at] multinet>:
> Am Montag, 14. September 2009 18:30:26 schrieb Ciro Iriarte:
>> Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
>> would like to know if anybody has done something similar. My main
>> doubt is about using ClusterIP or a loadbalancer with LVS in front of
>> the two nodes. LVS would imply a third machine and i'm not sure how
>> the origin of the outgoing connections (IP address) is handled by
>> ClusterIP.
>>
>> Any comments?.
>
> Well, LVS does not nescessarly need a third machine. See:
> http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-
> HOWTO.localnode.html#two_box_lvs
>
> I would use two machines and put the following software on the machines:
> - Mail Application: potfix, cyrus
> - Load Balancer: LVS, ldirectord
> - pacmaker for the high availability.
>
> then you have high availabiliy, load balancing and nearly unlimited
> scalability. ldirectord integrates very nicely into a pacemaker cluster.
>
> Please feel free to contact me for further question.
>
> Greetings,
>
> --
> Dr. Michael Schwartzkopff
> MultiNET Services GmbH
> Addresse: Bretonischer Ring 7; 85630 Grasbrunn; Germany
> Tel: +49 - 89 - 45 69 11 0
> Fax: +49 - 89 - 45 69 11 21
> mob: +49 - 174 - 343 28 75
>
> mail: misch [at] multinet
> web: www.multinet.de
>
> Sitz der Gesellschaft: 85630 Grasbrunn
> Registergericht: Amtsgericht MÃ¼nchen HRB 114375
> GeschÃ¤ftsfÃ¼hrer: GÃ¼nter Jurgeneit, Hubert Martens
>

Is that configuration reliable?, have you used it in production?.
Would that be better thatn ClusterIP?. Sounds great to drop that SPOF.

Regards,

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

misch at multinet

Sep 14, 2009, 10:16 PM

Post #6 of 12 (1798 views)
Permalink

Re: eMail server cluster [In reply to]

Am Montag, 14. September 2009 18:54:36 schrieb Ciro Iriarte:
> 2009/9/14 Timo Schoeler <timo.schoeler [at] riscworks>:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
(...)
> Can you elaborate on you cyrus + cluster experience? (maybe out of
> band if it's OT), OCFS2 1.4.0 supports shared writeable mmap now,
> which seems all that is needed to run cyrus on top of it.
>
> Regards,

Hi,

I never build a mail server cluster myself, but severeral others. I would be
pretty caucious to use cluster filesystems. There are few distributions
(SLES11, ...) which support it out of the box. You would have to search for
unsupported repositories. Better use NFS. ( NFS Server on the cluster and both
nodes are NFS clients)

If you want to use OCFS2, be sure to use the distributed lock manager (dlm)
and make o2cb use the pacemaker stack for communicataion. This also needs a
recent kernel.

> Is that configuration reliable?, have you used it in production?.
> Would that be better thatn ClusterIP?. Sounds great to drop that SPOF.

ClusterIP also does not have a SPoF. But LVS has some advantages over like
- persistancy: All clients use the same server within a time frame, not only
in a TCP connection
- forwarding based on "Weighted least connection", nut just round robin.
- phase out real servers with a weight of "0". No new connections are
forwarded to that server, but packages for established connections are. Ideal
for maintainance.

Greetings, Michael.
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

misch at multinet

Sep 15, 2009, 12:02 AM

Post #7 of 12 (1795 views)
Permalink

Re: eMail server cluster [In reply to]

Am Montag, 14. September 2009 18:54:36 schrieb Ciro Iriarte:
> 2009/9/14 Timo Schoeler <timo.schoeler [at] riscworks>:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > thus Ciro Iriarte spake:
> >> Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
> >> would like to know if anybody has done something similar. My main
> >> doubt is about using ClusterIP or a loadbalancer with LVS in front of
> >> the two nodes. LVS would imply a third machine and i'm not sure how
> >> the origin of the outgoing connections (IP address) is handled by
> >> ClusterIP.
> >>
> >> Any comments?.
> >
> > Hi,
> >
> > I don't really see the need of a third machine (thusly possibly
> > introducing a SPOF) into this setup, as two machines (running postfix,
> > cyrus, etc.) may hold the shared virtual IP themselves.
> >
> > - From my experience, however, cyrus is not the best solution to be run
> > in a cluster. Maybe dovecot is worth a look?
> >
> > (I write this being a very long year cyrus user myself, but planning to
> > migrate to dovecot for various reasons, not only the 'cluster issue'.)
> >
> > HTH,
> >
> > Timo
> >
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v1.4.5 (GNU/Linux)
> > Comment: Using GnuPG with CentOS - http://enigmail.mozdev.org/
> >
> > iD8DBQFKrnEEO/2mgkVVV7kRAtEcAJ9Mh0rLUeOfXB098TRUKIdPKFRjnwCeN0a6
> > WEkHhTMamyB21hfd8Vr3/+4=
> > =CUX5
> > -----END PGP SIGNATURE-----
>
> Can you elaborate on you cyrus + cluster experience? (maybe out of
> band if it's OT), OCFS2 1.4.0 supports shared writeable mmap now,
> which seems all that is needed to run cyrus on top of it.
>
> Regards,

Hi,

I just wrote a HOWTO about pacemaker, DLM and OCFS2. See:
http://www.clusterlabs.org/wiki/Dual_Primary_DRBD_+_OCFS2

Greetings,
--
Dr. Michael Schwartzkopff
MultiNET Services GmbH
Addresse: Bretonischer Ring 7; 85630 Grasbrunn; Germany
Tel: +49 - 89 - 45 69 11 0
Fax: +49 - 89 - 45 69 11 21
mob: +49 - 174 - 343 28 75

mail: misch [at] multinet
web: www.multinet.de

Sitz der Gesellschaft: 85630 Grasbrunn
Registergericht: Amtsgericht München HRB 114375
Geschäftsführer: Günter Jurgeneit, Hubert Martens

---

PGP Fingerprint: F919 3919 FF12 ED5A 2801 DEA6 AA77 57A4 EDD8 979B
Skype: misch42
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
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Darren.Mansell at opengi

Sep 15, 2009, 4:40 AM

Post #8 of 12 (1799 views)
Permalink

Re: eMail server cluster [In reply to]

Hello.

We are currently using a Postfix master/master 2 node cluster,
load-balanced with ldirectord as a resource in Pacemaker/OpenAIS.

Seems very stable and works well so far. We use SLES11 HAE.

I've attached the config I use.

HTH.
Darren

-----Original Message-----
From: linux-ha-bounces [at] lists
[mailto:linux-ha-bounces [at] lists] On Behalf Of Ciro Iriarte
Sent: 14 September 2009 17:30
To: General Linux-HA mailing list
Subject: [Linux-HA] eMail server cluster

Hi, i'm planning to build a postfix+cyrus Active/Active cluster and
would like to know if anybody has done something similar. My main
doubt is about using ClusterIP or a loadbalancer with LVS in front of
the two nodes. LVS would imply a third machine and i'm not sure how
the origin of the outgoing connections (IP address) is handled by
ClusterIP.

Any comments?.

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

Attachments:

crm_configure.txt (1.35 KB)

ifcfg-lo (0.30 KB)

ldirectord.cf (0.35 KB)

sysctl.conf (0.58 KB)

cyruspy at gmail

Sep 15, 2009, 7:08 AM

Post #9 of 12 (1792 views)
Permalink

Re: eMail server cluster [In reply to]

2009/9/15 Michael Schwartzkopff <misch [at] multinet>:
> Am Montag, 14. September 2009 18:54:36 schrieb Ciro Iriarte:
>> 2009/9/14 Timo Schoeler <timo.schoeler [at] riscworks>:
>> > -----BEGIN PGP SIGNED MESSAGE-----
>> > Hash: SHA1
>> >
> (...)
>> Can you elaborate on you cyrus + cluster experience? (maybe out of
>> band if it's OT), OCFS2 1.4.0 supports shared writeable mmap now,
>> which seems all that is needed to run cyrus on top of it.
>>
>> Regards,
>
> Hi,
>
> I never build a mail server cluster myself, but severeral others. I would be
> pretty caucious to use cluster filesystems. There are few distributions

I'm not really confident yet as i've no heard of cyrus on top of
OCFS2. The requirement from management is to have a active/active
cluster for that task.

> (SLES11, ...) which support it out of the box. You would have to search for

We have SLES10SP2 available...

> unsupported repositories. Better use NFS. ( NFS Server on the cluster and both
> nodes are NFS clients)
>
> If you want to use OCFS2, be sure to use the distributed lock manager (dlm)

Is that configurable?

> and make o2cb use the pacemaker stack for communicataion. This also needs a
> recent kernel.

I've setup linuxha+pacemaker+ocfs2 before, but just for flat files or
specifically Oracle datafiles...

>
>
>> Is that configuration reliable?, have you used it in production?.
>> Would that be better thatn ClusterIP?. Sounds great to drop that SPOF.
>
> ClusterIP also does not have a SPoF. But LVS has some advantages over like

I've seen some concerns expressed on the link you have before, like
management complexity and failover issues.

> - persistancy: All clients use the same server within a time frame, not only
> in a TCP connection
> - forwarding based on "Weighted least connection", nut just round robin.
> - phase out real servers with a weight of "0". No new connections are
> forwarded to that server, but packages for established connections Â are. Ideal
> for maintainance.
>
> Greetings, Michael.
> _______________________________________________
> Linux-HA mailing list
> Linux-HA [at] lists
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
> See also: http://linux-ha.org/ReportingProblems
>

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

cyruspy at gmail

Sep 15, 2009, 7:12 AM

Post #10 of 12 (1797 views)
Permalink

Re: eMail server cluster [In reply to]

2009/9/15 <Darren.Mansell [at] opengi>:
> Hello.
>
> We are currently using a Postfix master/master 2 node cluster,
> load-balanced with ldirectord as a resource in Pacemaker/OpenAIS.
>
> Seems very stable and works well so far. We use SLES11 HAE.
>
> I've attached the config I use.
>
> HTH.
> Darren
>

Hi!, what do you use for MDA?. If I stay with
SLES10SP2+linuxha+Pacemaker, am I missing any exclusive feature of
SLES11?. Have you tested failover?. Do you use a clustered filesystem?

Regards,

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

misch at multinet

Sep 15, 2009, 7:25 AM

Post #11 of 12 (1793 views)
Permalink

Re: eMail server cluster [In reply to]

Am Dienstag, 15. September 2009 16:08:29 schrieb Ciro Iriarte:
> 2009/9/15 Michael Schwartzkopff <misch [at] multinet>:
(...)
> > I never build a mail server cluster myself, but severeral others. I would
> > be pretty caucious to use cluster filesystems. There are few
> > distributions
>
> I'm not really confident yet as i've no heard of cyrus on top of
> OCFS2. The requirement from management is to have a active/active
> cluster for that task.

does you management understand something of IT? Make an active/passive cluster
and tell them it is an active/active cluster since both machines are running
in a cluster?

> > (SLES11, ...) which support it out of the box. You would have to search
> > for
>
> We have SLES10SP2 available...

Perhaps. Ask your SUSE support. but I doubt.

> > unsupported repositories. Better use NFS. ( NFS Server on the cluster and
> > both nodes are NFS clients)
> >
> > If you want to use OCFS2, be sure to use the distributed lock manager
> > (dlm)
>
> Is that configurable?

No. As far as the developers told me OCFS2s own cluster stack is not reliable.

Greetings,

--
Dr. Michael Schwartzkopff
MultiNET Services GmbH
Addresse: Bretonischer Ring 7; 85630 Grasbrunn; Germany
Tel: +49 - 89 - 45 69 11 0
Fax: +49 - 89 - 45 69 11 21
mob: +49 - 174 - 343 28 75

mail: misch [at] multinet
web: www.multinet.de

Sitz der Gesellschaft: 85630 Grasbrunn
Registergericht: Amtsgericht München HRB 114375
Geschäftsführer: Günter Jurgeneit, Hubert Martens

---

PGP Fingerprint: F919 3919 FF12 ED5A 2801 DEA6 AA77 57A4 EDD8 979B
Skype: misch42
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

Darren.Mansell at opengi

Sep 15, 2009, 8:37 AM

Post #12 of 12 (1786 views)
Permalink

Re: eMail server cluster [In reply to]

We are just relaying mail so no need for MDA. I've used Dovecot and you
can get a really nice MySQL/Postfix/Dovecot virtual set up if you so
wished.

SLES 11 HAE is very nicely integrated so it's simple to set up. You get
reasonable versions of OpenAIS and Pacemaker, whereas I found SLES 10.2
to be a little buggy.

Failover is fine, we don't use a shared filesystem, just load-balanced
nodes so if a server goes down, any mails in its queue are kept there
until it is back. Quite a simple set up really.

-----Original Message-----
From: linux-ha-bounces [at] lists
[mailto:linux-ha-bounces [at] lists] On Behalf Of Ciro Iriarte
Sent: 15 September 2009 15:13
To: General Linux-HA mailing list
Subject: Re: [Linux-HA] eMail server cluster

2009/9/15 <Darren.Mansell [at] opengi>:
> Hello.
>
> We are currently using a Postfix master/master 2 node cluster,
> load-balanced with ldirectord as a resource in Pacemaker/OpenAIS.
>
> Seems very stable and works well so far. We use SLES11 HAE.
>
> I've attached the config I use.
>
> HTH.
> Darren
>

Hi!, what do you use for MDA?. If I stay with
SLES10SP2+linuxha+Pacemaker, am I missing any exclusive feature of
SLES11?. Have you tested failover?. Do you use a clustered filesystem?

Regards,

--
Ciro Iriarte
http://cyruspy.wordpress.com
--
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems
_______________________________________________
Linux-HA mailing list
Linux-HA [at] lists
http://lists.linux-ha.org/mailman/listinfo/linux-ha
See also: http://linux-ha.org/ReportingProblems

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