Hello Suresh,
The FC clients will experience an outage.
Suppose in your scenario that node1 is the filer you have taken
down. node1's FC clients will not be able to perform I/O to node1's
LUNs through node2, because the "cf disable" command prevented
node2 from placing a SCSI reserve on the node1 disks as part of the takeover
process. With an active/active pair of nodes, only the node that
owns the SCSI reserve for a disk can perform I/O to that disk, So,
the only way prevent an outage to the FC clients is to perform the cluster
takeovers and givebacks that are part of the NDU. Hope this helps.
Filers running 7.2.6.1, cfmode -- single image
FC clients, use DSM/MPIO to connect
If a non NDU upgrade is attempted
(after setting cf disable), will taking down 1 of the filers make the FC
clients use the passive path for failover, or will the FC clients experience
an outage? Note I am not doing “cf takeover” before bringing one
of the filers down. I’d just like to know what the client
failover logic is in this case.