<div dir="ltr"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 11"><meta name="Originator" content="Microsoft Word 11"><link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CKlemer%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C01%5Cclip_filelist.xml"><style>  </style> Hi . I agree with you !! About giving the admin to adopt or not the paranoid approach of not failing over the services. I supported in the past tru64 clusters & now days the HP serviceguard.( hpux & linux ). Hp decided not develops the serviceguard on linux anymore & we now start using Redhat-Cluster. Its seems that for very critical customers you need at least 2 fencing method !!! & there is another thing to be fix ASAP - when using HALVM - The needs of comparing which file is newer , the lvm.conf or the initrd.img. - Regards. Shalom. <div class="gmail_quote">On Fri, Mar 5, 2010 at 10:01 PM, brem belguebli <<a href="mailto:brem.belguebli@gmail.com">brem.belguebli@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Corey, Hi Corey I was talking about a watchdog not a kernel panic (sysreq...), on common (X86) hardware, most server vendors implement embedded hardware chips that could be used. Indeed, SCSI3 reservation/registration could be combined to this whole stuff to be sure about the nodes sanity. I think the choice should be given to the admin to adopt or not the paranoid approach of not failing over the services. 2010/3/4 Corey Kovacs <<a href="mailto:corey.kovacs@gmail.com">corey.kovacs@gmail.com</a>>: <div><div></div><div class="h5">> Brem, > > It's been my understanding that the kernel panic technique you are > describing essentially is undesirable for the fact that the kernel is in an > unknown state. Basically anything can happen. The OS doesn't have to do a > sync for an hba do flush etc. Since RedHat isn't in the business of building > there own hardware like HP(DEC), Sun, IBM, they take the next best route to > ensure that nothing from that problematic machine can affect the storage and > the only way to guarantee that is to remove power from the whole machine. > > VMS and Tru64 use the panic method but the other nodes will issue a > reservation on the scsi bus against that node to protect the storage. They > can do that because they know exactly how there hardware and implementation > of reservations work. > > Corey > > On Thu, Mar 4, 2010 at 5:32 AM, שלום קלמר <<a href="mailto:sklemer@gmail.com">sklemer@gmail.com</a>> wrote: >> >> Thanks to all !!!! >> >> <a href="mailto:Shalom.klemer@hp.com">Shalom.klemer@hp.com</a> >> >> On Thu, Mar 4, 2010 at 12:00 AM, Lon Hohberger <<a href="mailto:lhh@redhat.com">lhh@redhat.com</a>> wrote: >>> >>> On Wed, 2010-03-03 at 13:10 +0200, שלום קלמר wrote: >>> > Hi. >>> > >>> > I got 2 power supplies. But if someone by mistake pull the power >>> > cables , is that mean >>> > >>> > That the services will not failover ?? >>> >>> The problem is: >>> >>> no power = no ping + no DRAC access >>> no network = no ping, no DRAC access >>> >>> If there's no power, then it is safe to fail over. >>> >>> If there is no network (and power is OK), then it is not safe to fail >>> over. Failover in this case is very likely to produce data corruption! >>> >>> Because we can not tell which case happened, we do not fail over. >>> >>> -- Lon >>> >>> >>> -- >>> Linux-cluster mailing list >>> <a href="mailto:Linux-cluster@redhat.com">Linux-cluster@redhat.com</a> >>> <a href="https://www.redhat.com/mailman/listinfo/linux-cluster" target="_blank">https://www.redhat.com/mailman/listinfo/linux-cluster</a> >> >> -- >> Linux-cluster mailing list >> <a href="mailto:Linux-cluster@redhat.com">Linux-cluster@redhat.com</a> >> <a href="https://www.redhat.com/mailman/listinfo/linux-cluster" target="_blank">https://www.redhat.com/mailman/listinfo/linux-cluster</a> > > > -- > Linux-cluster mailing list > <a href="mailto:Linux-cluster@redhat.com">Linux-cluster@redhat.com</a> > <a href="https://www.redhat.com/mailman/listinfo/linux-cluster" target="_blank">https://www.redhat.com/mailman/listinfo/linux-cluster</a> > -- Linux-cluster mailing list <a href="mailto:Linux-cluster@redhat.com">Linux-cluster@redhat.com</a> <a href="https://www.redhat.com/mailman/listinfo/linux-cluster" target="_blank">https://www.redhat.com/mailman/listinfo/linux-cluster</a></div></div></blockquote></div> </div>