Re: [Linux-HA] quorumd - is anyone using it?
Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. I thought it is essential for any cluster with an even amount of nodes? How would you decide DR in a split-brain condition of two nodes without a quorum server? Is it possible? Cheers, Holger Regards, Lars -- Teamlead Kernel, SuSE Labs, Research and Development SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) Experience is the name everyone gives to their mistakes. -- Oscar Wilde ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: Re: [Linux-HA] quorumd - is anyone using it?
Оригинално писмо От: [EMAIL PROTECTED] Относно: Re: [Linux-HA] quorumd - is anyone using it? До: linux-ha@lists.linux-ha.org Изпратено на: Събота, 2008, Март 1 13:30:28 EET -- Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. I thought it is essential for any cluster with an even amount of nodes? How would you decide DR in a split-brain condition of two nodes without a quorum server? Is it possible? Yes, is possible. If you have 2 nodes just join a third node to the cluster without running any resources on it. There you go you have quorum without quorum server. I beleive the quorum server idea is not that simple to use it only when you have even number of nodes. Quorum server should be used in DR when you have 2 separate data centers. Quorum server must decide which site is down and grant quorum to the other one, even if it has less nodes. Imagine you have 5 nodes cluster. 3 nodes in site A, 2 nodes in site B. Network between both sites is down so site A has majority quorum thus continue to run the service. But what happens if site A is down? Site B must takeover the sevice but it has not majoroty quorum - 2 nodes only! Here comes the Quorum server. Site B contacts the quorum server (change in membership is detected). Quorum server has lost connection to the site A therefore it grants quorum to site B. Unfortunatelly Quorum server does not work in 2.1.3. I hope it get fixed ASAP. Regards, Atanas Cheers, Holger Regards, Lars -- Teamlead Kernel, SuSE Labs, Research and Development SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nьrnberg) Experience is the name everyone gives to their mistakes. -- Oscar Wilde ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: Re: [Linux-HA] quorumd - is anyone using it?
Îðèãèíàëíî ïèñìî Îò: [EMAIL PROTECTED] Îòíîñíî: Re: [Linux-HA] quorumd - is anyone using it? Äî: linux-ha@lists.linux-ha.org Èçïðàòåíî íà: Ñúáîòà, 2008, Ìàðò 1 13:30:28 EET -- Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. I thought it is essential for any cluster with an even amount of nodes? How would you decide DR in a split-brain condition of two nodes without a quorum server? Is it possible? Yes, is possible. If you have 2 nodes just join a third node to the cluster without running any resources on it. There you go you have quorum without quorum server. I beleive the quorum server idea is not that simple to use it only when you have even number of nodes. Quorum server should be used in DR when you have 2 separate data centers. Quorum server must decide which site is down and grant quorum to the other one, even if it has less nodes. Imagine you have 5 nodes cluster. 3 nodes in site A, 2 nodes in site B. Network between both sites is down so site A has majority quorum thus continue to run the service. But what happens if site A is down? Site B must takeover the sevice but it has not majoroty quorum - 2 nodes only! Here comes the Quorum server. Site B contacts the quorum server (change in membership is detected). Quorum server has lost connection to the site A therefore it grants quorum to site B. Unfortunatelly Quorum server does not work in 2.1.3. I hope it get fixed ASAP. Hm okay and what if the uneven node (3. or 5. or 7...) is off for maintenance. I am having an even node cluster again with the possibility of an evil even split-brain condition.. Is there no reliable way to solve this? Because of that I thought its the job of the quorum server. Cheers, Holger Regards, Atanas Cheers, Holger Regards, Lars -- Teamlead Kernel, SuSE Labs, Research and Development SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) Experience is the name everyone gives to their mistakes. -- Oscar Wilde ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: Re: [Linux-HA] quorumd - is anyone using it?
Well, in 2.1.3 quorum server seems not to work. I really need it for a DR cluster but I'm not able to make it work. The certs are ok, Heartbeat connects to the quorum server to obtain quorum but it seems that the quorum server does not return anything or returns invalid quorum. The result is resources cannot run anywhere due to lack of quorum. As I understand Quorum server is not part of the cluster. Heartbeat does not have to start it. One quorum server can serve many clusters. Quorum server is not SPOF. Heartbeat contacts the quorum server only when change in the membership is detected, for e.g. a member node has been disconnected. Under normal conditions the quorum server is not contacted. HA_quorum variable shows which quorum plugin should heartbeat use (Majority is the default one). How exactly it works I don't know. It seems that nobody knows anything about the quorum server except its creator. Alan R. is teh author as I've been told. Also there are some quorum server concept disagreements. If anyone knows anything more about the quorum server please share it with us. Thanks. Atanas Dyulgerov Оригинално писмо От: Michael Schwartzkopff [EMAIL PROTECTED] Относно: Re: [Linux-HA] quorumd - is anyone using it? До: General Linux-HA mailing list linux-ha@lists.linux-ha.org Изпратено на: Четвъртък, 2008, Февруари 21 19:28:45 EET -- Lars Marowsky-Bree schrieb: Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. Regards, Lars I would like to give it a try if somebody could explain me how it works. Please see my post to this list from Feb, 5th. http://www.gossamer-threads.com/lists/linuxha/users/45705?search_string=quorum;#45705 Thanks, Michael ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: Re: [Linux-HA] quorumd - is anyone using it?
Hi, On Fri, Feb 22, 2008 at 11:43:15AM +0200, Atanas Dyulgerov wrote: Well, in 2.1.3 quorum server seems not to work. I really need it for a DR cluster but I'm not able to make it work. The certs are ok, Heartbeat connects to the quorum server to obtain quorum but it seems that the quorum server does not return anything or returns invalid quorum. The result is resources cannot run anywhere due to lack of quorum. As I understand Quorum server is not part of the cluster. Heartbeat does not have to start it. One quorum server can serve many clusters. Quorum server is not SPOF. Heartbeat contacts the quorum server only when change in the membership is detected, for e.g. a member node has been disconnected. Under normal conditions the quorum server is not contacted. HA_quorum variable shows which quorum plugin should heartbeat use (Majority is the default one). How exactly it works I don't know. The variable should be set to one or more quorum plugins, like this: q1[:q2] The plugins are invoked in turn until one of them reports a non-tie status. It seems that nobody knows anything about the quorum server except its creator. Alan R. is teh author as I've been told. Alan influenced the design but I think that the implementation was done by another programmer from IBM. Also there are some quorum server concept disagreements. Perhaps you can find a trace of that in the lists' archives. Thanks, Dejan If anyone knows anything more about the quorum server please share it with us. Thanks. Atanas Dyulgerov ?? ? ??: Michael Schwartzkopff [EMAIL PROTECTED] ???: Re: [Linux-HA] quorumd - is anyone using it? ??: General Linux-HA mailing list linux-ha@lists.linux-ha.org ? ??: ?, 2008, 21 19:28:45 EET -- Lars Marowsky-Bree schrieb: Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. Regards, Lars I would like to give it a try if somebody could explain me how it works. Please see my post to this list from Feb, 5th. http://www.gossamer-threads.com/lists/linuxha/users/45705?search_string=quorum;#45705 Thanks, Michael ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: [Linux-HA] quorumd - is anyone using it?
Lars Marowsky-Bree schrieb: Hi all, is anyone actually using the quorum daemon? My assessment seems to suggest that it is not workable in any scenario; but maybe I have missed something? If not and I'm right, I am afraid that users might actually deploy it, thinking it solves something and then be very upset when it fails under fire. Possibly, the prudent action at this time is to disable it from the package and build by default, until it is completed. Regards, Lars I would like to give it a try if somebody could explain me how it works. Please see my post to this list from Feb, 5th. http://www.gossamer-threads.com/lists/linuxha/users/45705?search_string=quorum;#45705 Thanks, Michael ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
Re: [Linux-HA] quorumd - is anyone using it?
On 2008-02-21T18:28:45, Michael Schwartzkopff [EMAIL PROTECTED] wrote: I would like to give it a try if somebody could explain me how it works. That's the problem, I don't see how you can use it to build a working and reliable configuration ;-) ___ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
