are you talking about LUN Migration functionality in Navisphere or host based migration ?

Navi lun migration for the purposes of making the lun transparently larger to a host. Host based expansion is exactly the same regardless of mirrors being in effect.

I think you might need to explain in a bit more detail what your situation is and what you are trying to accomplish. What is the mirror set you are referring to (e.g. host based, MirrorView, etc.)

Without more info I don't think anyone can really provide any answers.

From what I read, you are trying to make the luns larger that you have MirrorView on. Is this correct?

If so, then check out the MirrorView doc:

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H2417_clariion_mirrorview_asynch_dr_wp_ldv.pdf

In the middle of page 23 there is a paragraph that starts with "When expanding a lun..."

Basically you can expand the lun in the background while mirroring is still running, and let it finish (I would think through lun migration or by creating Metalun) but the extra space will not be available until you the replication software is removed. This means breaking the mirror entirely and re-doing it. Plus, the other lun in the mirror needs to also be the new size.

There is a way to also avoid a full sync upon creating the mirror if you follow the steps in that guide.

-Ryan

2nd question can you lun migrate a mirrored lun to a lun of the same size, i guess i could do a quick lun expansion and then migrate the lun.

We generally try to avoid using metaluns where its possible.

Ok as an example I have a 50G LUN mirrored between two sites, from reading the linked doco I can.

1. Shutdown the host.
2. Sync the mirror.
3. Destroy the mirror.
4. Migrate the source and destination LUN to a new larger one.
5. Recreate the mirror with intial sync not required.
6. Power the hosts backup and do whatever the host expansion process is to use the new size.

Obviously this requires an outage and a substantial one if its a large LUN involved, but at least a full resync isn't required.

Is there any way to do this without having a server outage besides totally destroying the mirror, lun migration, then mirror recreation with a full sync.

Surprised that EMC wouldn't be working on something if theres not, as this is pretty much a routine operation on non mirrored LUN's for places I've worked.

Why ? for performance reasons metas are better since you're using more spindels !

In my shop, we avoid METAs as well, due to our CX3's having to many objects and we see severe management issues. Host I/O appears to be ok.

The more objects in Navisphere, the longer it takes to poll the objects. Flare 24 and 26 affected (maybe more), but definitely not 28 (due to Flare using Delta polling).

Check out this document:

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/h6099-navisphere-performance-in-large-configurations-wp.pdf

Also check out this Primus: emc176825

-Ryan

That's one I've never run into before... too many objects?