[Cluster-devel] [PATCH 0/2] NLM failover unlock
Wendy Cheng
wcheng at redhat.com
Mon Jan 7 05:31:09 UTC 2008
This submission is part of the patch sets added to support NFS server
failover where the specified export is moved from one physical server to
another. The technical discussions can be found at cluster-devel mailing
list archives:
https://www.redhat.com/archives/cluster-devel/2007-April/msg00028.html
The implementation has not changed much since first RFC. The external
interfaces, however, have been revised several times. During latest code
review, it was suggested using export path name as the interface. The
idea was subsequently prototyped but found difficult to implement. The
killing issue is the existing lockd reclaim code structure on backup
server. The associated export path name is difficult to retrieve (based
on client svc_rqst structure) when the reclaim call is invoked. The
details is explained in:
[1] http://people.redhat.com/wcheng/Patches/NFS/NLM/004.txt
Nevertheless, as commented by few IT folks who are current managing NFS
servers on daily basis, the lock dropping feature itself is useful,
regardless failover and/or cluster setup. This new patch set allows
system administrator (or cluster user mode applications) to drop NLM
lock on server based on any one of the following two criteria:
o Server in-bound IP address
o Export path name (with restriction - see above [1] for details)
The reclaiming grace period can only be set based on server in-bound IP
address and the associated patch set will be submitted after this patch
set is settled and accepted.
-- Wendy
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