Device limit on the host side

Question

Hi Gurus, I want to know the limit of devices which we can present on the host side for all OS flavours. Thanks

Ed_R1 · Answer

Quite a broad question, but ... well, yeah.

For Windows hosts, the OS will only scan for LUNs up to 255.

So practically speaking, you can't map more than that many to a single host.

The problem kicks in if you have multiple hosts though - they'll each only scan as far as LUN 0xFF so you'll have to start LUN offsetting. Not the end of the world, but somethign that's definitely a lot easier if you do it pre-implementation - having to unmap and remap a bunch of LUNs later is a massive nuisance.

jaimalhan · Answer

I want to know this limit for HPUX and Solaris. Can you please help.

dynamox · Answer

HPUX 11i v3 - 16384 LUNs (Maximum 32 paths per LUN) HPUX 11i v2 - 4096 LUNs (maximum 8 paths per LUN) HPUX 11i v1 - 2400 LUNs

dynamox · Answer

Solaris 9/10 - Emulex driver - 255 LUNs per target Solaris 9/10 - Leadville driver see this link http://nixstor.blogspot.com/2007/12/solaris-leadville-driver-stack.html

SKT2 · Answer

HP-UX 11i V2 has lesser LUNs mentioned comapred to v1 . Hop that is a typo?

dynamox · Answer

Thanks SKT ..fixed that.

qciti · Answer

I read that Windows can detect LUNs 0-255 per target.  If you are zoned to more than one array (target), can you exceed the 255 limit?  This is important since I want to make sure that a Windows server can be used to manage an environment with a large number of Symms.  The sum of all the gatekeepers from all the managed arrays on the server may exceed the 255 device limit in a large environment.  If the limit is indeed per target, then we will not run into any issues since we only assign about 8 gatekeepers to the server for each array.

dynamox · Answer

it's per target. Might want to check your HBA documentation as well but the numbers you are talking about ..you will be ok. http://technet.microsoft.com/en-us/library/cc773268%28WS.10%29.aspx

SKT2 · Answer

'For Windows hosts, the OS will only scan for LUNs up to 255'... this one sounds like 255 TOTAL , single or multiple targets do not matter. As Dynamox mentioned, just cross check

dynamox · Answer

i don't think it's 255 total, it's 255 per target, see here http://support.microsoft.com/kb/310072

Symmetrix

Device limit on the host side

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