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concatenated LUNs (or Meta LUN)

In my old environment we had a .... ahem.. 3 letter SAN. I had the ability to concatenated LUNs or "join" them logically on the storage side and present that to the host where the host would see the combined LUN's as one.

They call it a meta LUN. Is my 3020 able to present a LUN to a host that is an "aggregate" of more than one LUN?

Ultimately, I am going to have to collapse a file server with LAS into a VM that already has a 1TB volume/LUN.

Most of this data is end (L)user home directories and I dont want to "flex" my volume over the 1TB dedupe limit.

Thanks in advance.

Re: concatenated LUNs (or Meta LUN)

Hey George,

In the old days we used to concat (Horrible performace BTW), on a SAN using Veritas Volume Manager.

By your comment, I will assume you are talking Windows and not Unix, therefore I would investigate the option of concat with (native) Volume Management in the Windows box that will mount the LUN/LUNs or with Microsoft DFS product as an add on.

Hope this steers you in the right direction.

Anthony Feigl

Re: concatenated LUNs (or Meta LUN)

Your correct in that this is all for a windows box however it is a VM running on 3.5 ESX and this is all iSCSI for what that might be worth.

So, since windows is horrible when it comes to volume management, is there a way I can present two 1TB LUN's to that VM so it shows as a single drive leter in 2003?

Probably a better question for the VMware forums, so this question is over there too.

Re: concatenated LUNs (or Meta LUN)

So...not as much time to reply as I'd like....I think a key thing to keep in mind is how aggregates and flexible volumes work. Given that aggregates span across large #'s of disks/spindles...and so FlexVols and the LUNs inside inherit that benefit, there's not as much need for Meta LUNs to provide that higher spindle count benefit.

Re: concatenated LUNs (or Meta LUN)

As I understand it -- I'm not an expert on ~ahem~ 3-letter Storage, but NetApp uses a bit of different terminology: Basically, a Flexible Volume on a NetApp is similliar to a MetaLUN -- a Flexible Volume basically can contain 1 or more RAID groups, which are similiar to the LUNs you concantenate together to form a MetaLun.

I know that's an over simplification, but hopefully it answers your question.

Re: concatenated LUNs (or Meta LUN)

>>So, since windows is horrible when it comes to volume management, is there a way I can present two 1TB LUN's to that VM so it shows as a single drive leter in 2003?

Maybe windows volume mount points would do the trick?  You could have then have your data like:

G:\home (1TB size)

G:\projects (1TB size)

...etc

Then you could share out G:\ from the root so the user sees it as one share.  Or, instead of using volume mount points to create the hierarchy you could use DFS to visualize it in a myriad of ways.

Gotta ask though, why not use CIFS natively on the filer?  It's a whole lot easier to work with...users can do file level restores from snaphots, resizing vols is trivial (smaller and bigger), etc.