It's possible option - I even built cluster at home (taking FC disk system from a garbage bin -:)) but did not had enough time to proceed with it yet.
----- Original Message ----- From: "Sunil Mushran" <[EMAIL PROTECTED]> To: "Alexei_Roudnev" <[EMAIL PROTECTED]> Cc: "ocfs2-users" <[email protected]> Sent: Wednesday, October 04, 2006 10:08 AM Subject: Re: [Ocfs2-users] Re: FW: Use of OCFS2 file systems. > Feel free to contribute patches. > > Sunil > > Alexei_Roudnev wrote: > > >Unfortunately, it MAKES CLUSTER LESS STABLE. It works until network and SAN > >systems afe fine, but is not so good in failed situations. > > > >Even if we use OCFSv2 for idle file systems (which do nothing 90% of the > >time) , o2cb reboots nodes when lost heartbeat > >or (worst) network or (even worst) both... Instead of trying to recover > >without it (as I said 0- FS is in consistant state, > >no activity at all). > > > >It is not just OCFSv2 problem - Oracle CSS behave simular (butis much more > >stable in reality), and Linux HA cluster > >too (but it can use different heartbeat conenctions so it can be configured > >very reliable). > > > >You are right saying that _cluster software always have a tendency to fence > >or kill neighbours to keep > >internal consistancy_. But OCFSv2 is one of he worst examples of such > >software. > > > >What can be done _relatively easy_. > > > >(1) as we saiud many times - redundancy and better timeout control in > >heartbeat. (Of course, long timeouts means _long recovery_, but it's OK for > >90% > >installations). Typical network recovery is 1 minute, not 10 seconds. > > > >(2) System should not make bad things IF it is in consistant state. In many > >cases, if system have not outstanding IO requests, it can recover > >without server reboot (or at least try to do it) even if it lost heartbeats > >and suspect, that other systems could take control out of it. > >It is serious theoretical challenge _how to do it safely_, but it is very > >desired for such systems. > > > >(3) In some configurations, FS can be treated as _not so important_. It > >means that it is safer to switch into red_only and try to recover online, > >but not panic. Good example - you have production Oracle which uses ASM, and > >you use OCFSv2 for backup storage. IT is safer to make IOP failure on this > >storage vs rebooting system without reasons. > > > >PS. I had 2 network outages in the lab today,m because of bad UPS - and in > >all cases, ALL OCFSv2 servers (in 2 different clusters) rebooted. No one > >survived short (30 seconds) lost of Ethernet conenction (including iSCSI). > >In some cases, one server rebooted by OCFS and otehr by another part of the > >cluster (HA or RAC) - but result is exactly this - _all_ OCFSv2 panic on a > >shport network/san outage, in all cases. > > > > > > > > > >----- Original Message ----- > >From: "Sunil Mushran" <[EMAIL PROTECTED]> > >To: "ocfs2-users" <[email protected]> > >Sent: Tuesday, October 03, 2006 1:51 PM > >Subject: [Ocfs2-users] Re: FW: Use of OCFS2 file systems. > > > > > > > > > >>I try to avoid responding to such emails because I am not sure how > >>much credibility a partisan has in such debates. After all I have been > >>working on OCFS/OCFS2 the last 4/5 years. > >> > >>Having said that, I have some issues with the statements. While it is true > >>that we can improve on the disk/net heartbeat, it is wrong to say that it > >>does not work or makes the cluster unstable. > >> > >>We have OCFS2 running on lots of clusters in Oracle that are testing each > >>new revision of the database. While these machines are test boxes, they > >> > >> > >are > > > > > >>all running loads designed to break Oracle. I am rarely pinged about them > >>hitting an OCFS2 issue. > >> > >>We also have internal production databases as well as Oracle customers who > >>are using OCFS2 with much success. > >> > >>However, we do have room for improvement and we are working on it. > >> > >>For the list of ongoing projects, you can peruse the OCFS2 Development > >>Wiki at http://oss.oracle.com/osswiki/OCFS2. > >> > >>If you wish to contribute code, as this is an open source project, feel > >> > >> > >free > > > > > >>to ping me or the [email protected] mailing list. > >> > >>Thanks > >>Sunil Mushran > >> > >> > >> > >>>Hi Sunial, > >>> > >>>What are your thoughts about this message on the mailing lists? > >>> > >>>Thanks! > >>>Sanjeet > >>> > >>> > >>>------------------------------------------------------------------------ > >>> > >>>*From:* [EMAIL PROTECTED] > >>>[mailto:[EMAIL PROTECTED] *On Behalf Of > >>> > >>> > >*Alexei_Roudnev > > > > > >>>*Sent:* Friday, September 29, 2006 11:50 PM > >>>*To:* Bill Wells; Sunil Mushran > >>>*Cc:* [email protected] > >>>*Subject:* Re: [Ocfs2-users] Use of OCFS2 file systems. > >>> > >>> > >>> > >>>If you can avoid OCFSv2 on a RAC server, better do it. Any cluster > >>>(RAC and OCFS) have it's own instability elements (OCFSv2 have a poor > >>>heartbeat alghoritm and so tend to self-fence without real failure, > >>>and (in addition) is relatively new. It works fine enough to be used, > >>>when you really need file sharing (such as database files or backups > >>>or even archive logs), but the less you use it, the better. Oracle > >>>home files feels well without sharing. > >>> > >>> > >>> > >>>// I don't see problems with OCFSv2 on SLES9 SP3-updated, but I avoid > >>>to use it for mission critical file systems or heavy-duty file systems, > >>> > >>>// and I still have failure scenario, when RAC cluster could work but > >>>OCFS cause full-cluster failure > >>> > >>>// If you have network problem, SAN > >>> > >>>// system restart, disk io error, etc etc - you can end up with system > >>>panic or reboot, caused by OCFS - > >>> > >>>// so the less OCFS you have, the better is your system stability. > >>> > >>> > >>> > >>_______________________________________________ > >>Ocfs2-users mailing list > >>[email protected] > >>http://oss.oracle.com/mailman/listinfo/ocfs2-users > >> > >> > >> > > > > > > > > _______________________________________________ Ocfs2-users mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-users
