PowerPath question 1

[Mag0007]

Currently I have 2 HBA. These HBA are attached to 60 SAN disks each (1 HBA has 60 hdisks associated with them, another HBA has another 60 disks associated with them). Currently there is no powerpath or multiple path software installed on my system. Now if I wanted to install EMC powerpath, would my disks disappear? Has anyone does this before, regular fiber hdisks to hpowerdisks?

TIA

 

[trisco]

At my previous place, I installed EMC PowerPath. Follow the install instructions that come with it. You will have to remove each of your current PV's and after PowerPath installation, run cfgmgr on each of the adapters. Then there are some additional PowerPath commands.

 

[Mag0007]

Will it remove the data on the disks?

 

[p5wizard]

Installing a new device driver for a type of disk shouldn't alter any data on the disks.

You will probably first have to unmount all FSs, exportvg all VGs, remove all the disks, then install new device driver, run cfgmgr and then you'll have the same LUNs again, now as powerpath devices. From then on, you need to importvg your VGs and then you'll be able to mount your FSs again. (There should be some info on "howto" together with the EMC installation set?)

I don't have any experience with EMC or powerpath, but at some point you may need to be able to identify which device is which LUN, preferably you want to be able to correlate which hdisk (you have now) is which powerpath device after the operation. If you're unable to identify which disk is which EMC LUN "before", then you'll have to identify which disk is which based on the PVID, which you can read "before" and "after" with the lspv command. A PVID is written by LVM on first use of a disk and that shouldn't change either by this operation.

This is something you probably want to try out on a test server first.

HTH,

p5wizard

 

[Mag0007]

Nice, thanks for the explaning and the confidence booster p5wiz!

 

[kHz]

inq will give you the powerpath device to hdisk correlation.