[Linux-cluster] GFS and HEARTBEAT
Lon Hohberger
lhh at redhat.com
Thu Jan 27 18:49:12 UTC 2005
On Thu, 2005-01-27 at 13:36 -0500, Lon Hohberger wrote:
> However, it should be possible to run GFS as the backend store for
> services/resource groups managed by heartbeat, but be aware that
> heartbeat's notion of membership and GFS's may not always coincide (e.g.
> one might think node X is offline, while the other believes it to be
> online).
Sorry, forgot to explain the practical implication. As an example:
1 - Heartbeat detects that node A is offline.
2 - Heartbeat STONITHs node A and takes over services.
3 - (30 seconds pass)
4 - GFS detects that node A is offline.
5 - GFS fences node A and recovers node A's journal.
6 - Cluster in sane state.
In the above case, it's mostly just annoying for the system
administrator and causes node A to be unavailable for longer than
necessary.
(If GFS locks are held when node A dies, then it becomes a bit more
complicated.)
-- Lon
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