LUN device path

[Kenneth Yap]

Hi Experts,
My customer have one unit L-class server direct connect to FC60 disk array.
If we add in a FC 8 port switch connection from server to FC switch and FC switch to FC60 disk array. Did the server still can scan back the the original LUN device path ?

[Michael Tully]

Hi Kenneth,

If you change from direct connect to a FC switch, the hardware paths will certainly change.

You can of course do a vgexport/vgimport to reclaim the same disks/volume groups/logical volumes.

All you would need do is:

Full backup (pre-requisite to any type of change)
# vgexport -m myvg.mapfile -v -p -s /dev/myvg (for each volume group)
(make sure you keep the mapfiles on your internal disk somewhere.)
Connect your cable(s) to FC switch, complete your zoning.
# vgimport -m myvg.mapfile -v -p -s /dev/myvg (for each volume group)
# vgimport -m myvg.mapfile -v -s /dev/myvg (for each volume group)

HTH
Michael

[Leif Halvarsson_2]

Hi,
There have been some question about this in the storage forum and, I am afraid, the answere is no. You have to import the volumegroups after connecting to a switch. Make sure you have a good backup before.

[Eugeny Brychkov]

Agree with everyone. Will change.
In addition, FC60 is NOT supported in fabric. Only in private loop. This means that your FC60's switch port should be configured in quickloop
Eugeny

[Pete Randall]

Kenneth,

As stated, LUN paths will change. I'm curious, though, why they would want to do this. It sounds to me like they must be thinking about sharing the FC60 between multiple servers. If that's the case, let me point out that it does work (I've done it), but HP will not support such a configuration.


Pete

[Karamanolis Nikos]

Hi Pete,

We run it like you said (FC60 shared between 2 N4000) and, at least here in Greece, HP does support it.

And not only supports it, but already replaced the whole thing (FC60 controllers,3 SC10, full with 18G disks) because there where problems with the Array going off-line from time to time...

Must admit that this was beyond my (and customers) any expectation.

[Sunil Sharma_1]

No device path will cahnge.
and you may required to do a vgexport and vgimport but you can try this also may work.
#mv /etc/lvmtab /etc/lvmtab.old
#vgscan -v

Sunil