Fredrich, Some time ago, Richard Elling did a nice little spreadsheet showing that the overall availability of the cluster went down if you added multiple QDs or QSs. Basically, it was due to the increased likelihood that one of them would have failed. Bottom line: one QS or QD is enough.
Regards, Tim --- On 10/20/09 15:51, Fredrich Maney wrote: > On Tue, Oct 20, 2009 at 8:55 AM, Tundra Slosek <ivoryring at gmail.com> wrote: >> I have not yet. Am I misunderstanding my reading of the documentation, that >> a quorum server is a single point of failure for the cluster (i.e. the >> cluster's availability won't be any higher than the quorum server's). As it >> stands, I'm a little surprised because my '4 node HA cluster' seems to be >> less tolerant of failure than a pair of 2-node clusters would seem to be - >> with one of the four nodes out of the cluster, a reboot of one of the >> remaining 3 causes the other 2 to panic and reboot. I think I understand >> that this is intentional to avoid a partition, but it really feels like '4 >> node cluster' is no more available than '3 node cluster'. If I'm going to >> add a 5th machine for no purpose other than to be the quorum server, would I >> be better off making the 5th machine a 5th node? > > The QS is a very light weight process (about on par with NTP) that can > run on pretty much any other server outside of the cluster nodes with > no impact. It can also be used as the QS for multiple clusters. Also, > if you are truly worried about it being a SPoF, you could have more > than one of them on different machines - or even an HA clustered QS. > Though that would probably be taking things a bit far. > >> My current experiment, which I'm working on setting up, is to have the >> Private Interconnect occur over physical NICs that are not shared for any >> other purpose. If that doesn't work, I'll try a quorum server. Either way, >> I'll keep this thread updated as I go. > > Unless you are using VLAN tagging, you are required to use dedicated > NICs for the Interconnect. > > fpsm > _______________________________________________ > ha-clusters-discuss mailing list > ha-clusters-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/ha-clusters-discuss -- Tim Read Staff Engineer Solaris Availability Engineering Sun Microsystems Ltd Springfield Linlithgow EH49 7LR Phone: +44 (0)1506 672 684 Mobile: +44 (0)7802 212 137 Twitter: @timread ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NOTICE: This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
