Format and mount the SAN LUN.
Start a write to the mounted filesystem cat /dev/zero >> /pathto/mnt/testfile &
Now connect to the multipath daemon in interactive mode multipathd -k
View current paths with show maps topology
multipathd> show maps topology
reload: mpath5 (360060e801045249004f2a5f900000031) dm-7 HITACHI,DF600F
[size=128G][features=0][hwhandler=0][rw]
_ round-robin 0 [prio=1][active]
_ 1:0:0:4 sdb 8:16 [active][ready]
_ round-robin 0 [prio=0][enabled]
_ 2:0:0:4 sdc 8:32 [active][ready]
There are two paths shown as sdb and sdc. Delete one path.
del path sdb
Suspend with ctrl-z and check that the write is still happening.
ls -l /pathto/mnt If testfile is still growing then the path sdc is working.
Resume multipath with fg 2. Re-add the path.
add path sdb
Now remove the other path.
del path sdc
Again suspend iwth ctrl-z and check that the test file is growing. If so
then resume multipath and re-add the path.
add path sdc
Testing complete. Exit with ctrl-c. Kill the write job with kill %1. Remove
the test file.
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Tags:
multipathd
iscsi
san
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