BarbaroB wrote:
Can I export VV to 2 host sets at the same time and delete 1 like you explained here?
viewtopic.php?f=18&t=229&p=657&hilit=unexport#p657Yes you can export a LUN to 2 HostSets, however the gotcha with your environment is that the same hosts are members of both host sets. So Datastore1 might be LUN #1 on all your systems per your existing vlun template. Then you create a new HostSet, and add your ESX 3.5 hosts... your ESX 3.5 hosts are now in both host sets, and still have a LUN #1... then you go a create a new export of that Volume that contains Datastore1, the system knows that LUN #1 is already in use, so it increments that to LUN #2... now your ESX hosts see a LUN#1 as Datastore1 and now they also see a LUN#2 which also appears to have a datastore already on it...
I don't know what will happen, perhaps a VMware expert can add some wisdom here... but I have some theories:
1) the 3PAR system will realize that host already sees that VV and will not create the new export.
2) the 3PAR system doesn't care and creates the new export, but forces a new LUN# because the old one is already in use.
2a) ESX 3.5 sees a new LUN and does not recognize it as an already mounted datastore and possible corrupts the data.
2b) ESX multipath kicks in and adds the new LUN as additional paths the data store already mounted 2c) The situation causes a fold in the time space continuum forming a black hole, destroying everything.
Can you take an partial outage of just one of the 2 ESX environments to facilitate the split?
You could pre-stage a lot of the work:
Create the new HOSTSET for ESX 3.5, leave it EMPTY.
Export the proper ESX 3.5 luns for to the EMPTY ESX 3.5 host set. You can even go so far as to match up LUN#'s so that if it was LUN3 on the old layout, it will remain LUN3 on the new. Then wait for a maintenance window... shutdown the ESX 3.5 environment, remove the ESX 3.5 hosts from the OLD host set, add them to the new host set, power them on.