IBM DS 8300 SAN reporting different LUN friendly name than CentOS.
Hello,
I found a weird behaviour regarding reported friendly names comparing multipath
on Debian 5.0.3 and CentOS 5.3 accessing a SAN IBM DS8300 [0] LUNs.
Output snippet of both multipath -l -v3 commands:
Debian:
36005076308ffc36c0000000000001107dm-5 IBM ,2107900
[size=200G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=0][active]
\_ 2:0:0:5 sdg 8:96 [active][undef]
\_ 2:0:1:5 sdq 65:0 [active][undef]
\_ 0:0:0:5 sdaa 65:160 [active][undef]
\_ 0:0:1:5 sdak 66:64 [active][undef]
CentOS:
36005076308ffc36c0000000000001107 dm-0 IBM,2107900
[size=200G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=0][active]
\_ 1:0:0:5 sdaa 65:160 [active][undef]
\_ 1:0:1:5 sdak 66:64 [active][undef]
\_ 3:0:0:5 sdg 8:96 [active][undef]
\_ 3:0:1:5 sdq 65:0 [active][undef]
As you can see, the same wwid is reported as dm-5 by Debian and dm-0 by CentOS.
Being listed at both machines as /dev/dm-0 (susscesfully configured lvm over
them) what will happen if multipath.conf is configured following the CentOS
reported dm-0 or the Debian dm-5?
I "guess" that as far as vg groups and lv are created using /dev/mapper/*
friendly names reported by multipath instead of direct /dev/dm-* devices, and
multipath.conf configured carefully using the correct wwid, should be all right.
There are some lv created at both machines already, over directly grouped
/dev/dm-* devices instead of /dev/mapper/* ones.
I do not have physical access to the machines, nor previous experience with
these san.
Any suggestions or urls to read?
Thanks.
Andre Felipe Machado
[0] http://www-03.ibm.com/systems/storage/disk/ds8000/
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