Messages in this thread | | | Date | Tue, 9 May 2006 02:24:58 -0500 | From | "Circuitsoft Development" <> | Subject | Re: Fwd: Fwd: Extended Volume Manager API |
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On 5/8/06, Lars Marowsky-Bree <lmb@suse.de> wrote: > On 2006-05-08T16:17:07, Circuitsoft Development <circuitsoft.devel@gmail.com> wrote: > > > I'm not. They also need to get permission from the network before they > > write to the disk, and they're not going to get permission without > > hearing back from everybody. Besides, since the same network is used > > to connect to the disks as is used to connect the computers to each > > other, how would it be able to access the disks without being able to > > access other computers which also connect to the disks? > > You really should read up about split-brain scenarios
I don't see how they'll happen if the heartbeat/management runs over the same network that is used to connect to the disk.
> quorum
I'm aware of the idea. I think that a static quorum would be best, and that it should be configured by the cluster administrator. See http://lists.osdl.org/pipermail/osdlcluster/2004-January/000071.html for a description of the problem with dynamic quorum.
> IO fencing
The primary target storage protocol is ATA-over-Ethernet, second is iSCSI. As far as I know, it should be relatively simple, in both circumstances, to tell the storage blade to cut off a computer until it correctly re-registers itself with the cluster. Otherwise, a CISCO managed switch should also be able to cut off a computer if it stops responding to the cluster.
> cluster membership algorithms
Having trouble finding too many details on these. I'll keep looking, but some pointers could be helpful.
> and the amazing variety of different types of crashes.
I figured that IO Fencing combined with STONITH (Shoot The Other Node In The Head) could solve the problems caused by most crashes.
> > Sincerely, > Lars Marowsky-Brée > > -- > High Availability & Clustering > SUSE Labs, Research and Development > SUSE LINUX Products GmbH - A Novell Business -- Charles Darwin > "Ignorance more frequently begets confidence than does knowledge" >
These thoughts are based on my best understanding of how-stuff-works so far. Any further comments would be greatly appreciated.
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