13erla
Enthusiast
Enthusiast

2048gb limit on luns? esx301

i have esx301 connected to an EMC SAN.

i have a 2TB lun set at 2048gb. i see this after scanning as 0bytes.

i have another 2tb lun set at 2046 that i can see fine.

is 2048 the end all limit a lun can be? i've read some posts were people speculate. but is this really the end all be all limit a lun can be without doing Expanding?

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7 Replies
davidbarclay
Virtuoso
Virtuoso

Correct, that is the limit.

See here[/url] for details.

but is this really the end all be all limit a lun can be without doing Expanding?

I assume you mean the use of extents. Yes you can do this and go to 64TB...but do you really want to?

Most of us don't use or recommend extents.

Dave

Message was edited by:

davidbarclay - hyperlinked url

13erla
Enthusiast
Enthusiast

i'm connecting the 2TB via Raw Mapping.

no i don't plan to do any extents.. i use the standard BP of 256gb luns for vmdks.

however would >2048 be the limit of the allocation of a LUN? without using extents

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davidbarclay
Virtuoso
Virtuoso

AFAIK, regardless whether you are using VMDK, RDM or even regular LUN to linux/windows - you won't be able to go over 2048GB without some sort of extent/cluster/etc to span.

Dave

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jjamieson
Enthusiast
Enthusiast

Yes, that's been my experience. Any LUN over 2TB will not even appear to be detected; you need the LUN to be available to ESX whether or not you use it as a VMFS or RAW mapping.

I've tried both, and the 2TB limit is across the board.

Of course, it's really not all that much of a "limit" since 2TB is still a lot of storage for a single LUN by today's standards and almost any data that might use that much can almost always be spanned (or SHOULD be!)

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Steve_Mc
Hot Shot
Hot Shot

The largest LUN that can be presented to any current version of ESX (2.5x and VI3) is 2TB minus 1 sector.

This means if you want a 2TB LUN you will want to bind the LUN as 2047GB. If you bind as 2048GB the ESX server will not recognize it (will display as 0 bytes).

Steve

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jjamieson
Enthusiast
Enthusiast

In my case (QLA2340's connecting to CX700) the volumes simply do not show up in the list at all.

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13erla
Enthusiast
Enthusiast

i've found that creating a LUN at 2046gb and you will be as close to 2TB as possible. without doing any extends.

i have this on a CX500

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