Lun’s selection in 2 node rac

[satish]

Dear erman,

In one of the site written by you..

The disks which will be presented by SAN should be in form of 8 lun( For ex:  rather than having 1x 1600 gb , we prefer  8x200 gb luns) We want 8 luns because the environment has multipath with 2 active paths, thus we prefer active path *4 luns for ASM. Disks should be aligned for ASM use..

We need 600gb for data diskgroups and 600 go for RECO disk group.We are going for 3 Luns each of 200 Gb for data dg and 3 Luns for reco dg.We have 2 paths.

 1)selecting number of Luns have any dependency on io path as well?
2)will there be any option in storage to make same lun available to both rac servers?Any idea how they will achieve this briefly.

Pls suggest best practice.

Thanks,
Satish

[ErmanArslansOracleBlog]

I like your choice , I mean 8x200GB against 1x1600GB :) Correct.

1)Not really.. But! Check with your storage admin. Check their best practices with Oracle & ASM
2)Ofcouse yes.. You do the cabling.. Most of the time we use Fiber (+FCP protocol) for that (Sotage + SAN switch etc..) and then you map them to your RAC machines.. You check/rescan your scsi and that's it.. Ofcourse yes, you need too make them available for both of the RAC servers, because we need them be accessible from both of the RAC nodes.. We use shared everything arch.. ( we don't use shared nothing arch in RAC).. So, if you are asking about ASM disks , my answer is .. But if you are asking this for OS disks, my answer is you shouldn't, that is a no. Shared Oracle , Non-Shared Oracle home , these are just details.. I guess you already got your answer..

[satish]

Dear Erman,

Thanks for the update.

"Ofcourse yes, you need too make them available for both of the RAC servers"--This will be done by storage admin?
Once that is done,only then we can proceed with scsci scan,multipathing,creating asm disks etc...

Thank You

[ErmanArslansOracleBlog]

Yes Storage Admin will do that. OS admin will also take some actions that I mentioned earlier, after the Storage admin maps the luns.

[satish]

Thank you