Re: Cyrus failover steps
- Matthew Seaman [EMAIL PROTECTED] wrote: On FreeBSD, CARP would be the natural choice, seeing as it's standard with the system. All you need is to build a kernel with 'device carp' added to the config file and to have read the carp(4) manual page. Then just add something like: cloned_interfaces=carp0 ifconfig_carp0=vhid 100 pass CENSORED 192.168.23.45/24 to /etc/rc.conf on both machines. Reboot, et voila: the 192.168.23.45 IP will float between the two servers. But magical floating could be a problem for Cyrus. Think of a case where the master fails, the IP floats to the replia, some mail is delivered, the master comes back up, and the IP moves back. Oops... the mail delivered to the replica is now invisible and effectively lost. CARP kinda of loses for application failover, as there is no way to fire a script before moving the IP, and before moving the IP back. It will probably grow some scriptability at some point. But for the time being, CARP is better for firewalls and routers than services. Also, there can be split brain issues, where both nodes think they are the master. Or issues where a node will hold onto an IP even though it is actually dead. But HeartBeat can do this. Tom Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
Re: Cyrus failover steps
Hi, Matthew Seaman wrote: On FreeBSD, CARP would be the natural choice, seeing as it's standard with the system. ... CARP works nice for a floating IP-address between two servers, and if you go that route you might want to look at ifstated (in the ports) to control daemons based on the CARP failover... (With heartbeat (linux-ha) you can control services as well as the IP-addresses...) But I'm not sure if this automatic failover is wise for use with Cyrus replication. At least I still do my failovers manually; I still like some more control over where my master actually is, when I recover, verify that the last bits are properly synced (if possible run a sync_client on the remaining logs), verify that replication was actually working, verify that there is indeed something wrong, perhaps compare md5s, ... Just some checks but if a failover occurs with a slave that was accidentally not up to speed you'll lose (the not yet synced) mail on the previous master (if I'm not mistaken). And you can't have a sync server and sync client at the same time and have imapd running on both servers (then you'd only redirect your clients to the server running the master imapd with the CARP failover)... That said, I don't have a written 'protocol' for it yet, and I'd still like to automate a couple of things, I was thinking of cfengine or something like that so I can only flip a switch to change roles (and still be carefull)... but for the application I think it's more dangerous to rely on CARP; it might just switch addresses while the application isn't ready for that. (We have stunnel, http proxies, resolvers and in/outgoing MTAs, those work perfectly with CARP - even without ifstated...) Paul Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
Re: Cyrus failover steps
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Scott M. Likens wrote: Hi Ilya, there are many methods for failover. One is heartbeat, According to Freshports you have a version of Heartbeat available. http://www.freshports.org/sysutils/heartbeat/ it's web site is http://www.linux-ha.org Should give you some reading. Scott On FreeBSD, CARP would be the natural choice, seeing as it's standard with the system. All you need is to build a kernel with 'device carp' added to the config file and to have read the carp(4) manual page. Then just add something like: cloned_interfaces=carp0 ifconfig_carp0=vhid 100 pass CENSORED 192.168.23.45/24 to /etc/rc.conf on both machines. Reboot, et voila: the 192.168.23.45 IP will float between the two servers. On Fri, 11 May 2007 13:34:20 -0400 Ilya Vishnyakov [EMAIL PROTECTED] wrote: Hello Cyrus Gurus! I set up cyrus replication on our freeBSD 6.2 boxes. I used this tutorial. http://cyrusimap.web.cmu.edu/imapd/install-replication.html Could someone please suggest a documentation on How to failover from one server to another in case of emergency? I googled and googled and couldn't find anything. Please point me to the right direction , don't let me to ruin all the mailboxes. Thank you in advance. Cheers, Matthew - -- Dr Matthew SeamanThe Bunker, Ash Radar Station PGP: 0x60AE908C on servers Marshborough Rd Tel: +44 1304 814800 Sandwich Fax: +44 1304 814899 Kent, CT13 0PL, UK -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.3 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGRaom8Mjk52CukIwRCNutAJ9wVnwlnqFrmOTYq93bJfVp7UtSOQCgh1f5 wcEiH9Z3s0m8JfhPh1yfaJs= =UEkc -END PGP SIGNATURE- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
Cyrus failover steps
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hello Cyrus Gurus! I set up cyrus replication on our freeBSD 6.2 boxes. I used this tutorial. http://cyrusimap.web.cmu.edu/imapd/install-replication.html Could someone please suggest a documentation on How to failover from one server to another in case of emergency? I googled and googled and couldn't find anything. Please point me to the right direction , don't let me to ruin all the mailboxes. Thank you in advance. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGRKkcUZGmaUWxLn8RAm7OAKCp/YyZ86diMaYP0PtaNKejDWM8QwCeK/N4 BdQJMfZutSS37eqduzqf4MI= =NtVI -END PGP SIGNATURE- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
Re: Cyrus failover steps
Hi Ilya, there are many methods for failover. One is heartbeat, According to Freshports you have a version of Heartbeat available. http://www.freshports.org/sysutils/heartbeat/ it's web site is http://www.linux-ha.org Should give you some reading. Scott On Fri, 11 May 2007 13:34:20 -0400 Ilya Vishnyakov [EMAIL PROTECTED] wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hello Cyrus Gurus! I set up cyrus replication on our freeBSD 6.2 boxes. I used this tutorial. http://cyrusimap.web.cmu.edu/imapd/install-replication.html Could someone please suggest a documentation on How to failover from one server to another in case of emergency? I googled and googled and couldn't find anything. Please point me to the right direction , don't let me to ruin all the mailboxes. Thank you in advance. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGRKkcUZGmaUWxLn8RAm7OAKCp/YyZ86diMaYP0PtaNKejDWM8QwCeK/N4 BdQJMfZutSS37eqduzqf4MI= =NtVI -END PGP SIGNATURE- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html !DSPAM:4644b4fd253086491211187! -- What does one want when one is engaged in the sexual act? That everything around you give you its utter attention Think only of you, care only for you... Every man wants to be a tyrant when he fornicates Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
