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Karl999

17 Posts

2281

June 7th, 2007 05:00

maximum lun size

Is there a maximum LUN size on a cx500 with flare 19? I think I was told at one point it was 535GB but I can't find it in my notes and no luck searching for it.

thanks

AranH1

2.2K Posts

June 7th, 2007 07:00

The maximum LUN size is going to be limited by the OS more than the storage array at FLARE 19 and above.

Here is a thread on max LUN size for NTFS:
http://forums.emc.com/forums/thread.jspa?threadID=51742&tstart=0


Here is a thread on max LUN size for Solaris:
https://forums.emc.com/forums/thread.jspa?threadID=54274&tstart=0

Karl999

17 Posts

June 7th, 2007 09:00

Ok. I was told by a local consultant that it was 500GB for a single lun (not a metalun).

thanks

DGM3

238 Posts

June 7th, 2007 11:00

Ok. I was told by a local consultant that it was 500GB for a single lun (not a metalun).


Kreischl,
The 500GB (or 535GB) limit doesn't sound right... in older revs of Flare, there used to be a limit of 2TB less 1 sector, but with current releases (including R19) a metaLUN can be constructed that (if desired) consumes all capacity within the entire array.

If metaLUNs are not used, the limiting factor becomes the size of the RAID Group (assuming you configure a single LUN within the RAID Group that consumes all of the RAID Group's capacity). So if using maximum width RAID Groups; that would yield 16 x disk capacity for a 16-drive RAID 0, 15 x disk capacity for a 16-drive RAID 5, or 8 x disk capacity for a 16-drive RAID 1/0.

Regards,
DGM

Karl999

17 Posts

June 7th, 2007 11:00

Thank you for the feedback. It's hard to get good consultants around here.

ShaunCarter

2 Posts

June 8th, 2009 03:00

I have opened this thread in search of knowledge too, I was aware of the 2TB limit, as you say though this is quite an old figure, I am now running r26/28, and can't find any info as to whether this figure has got any larger. Any info (or links to official documentation would be appreciated). :)

DGM3

238 Posts

June 8th, 2009 22:00

ShaunC,
In current releases of FLARE (including R26 and R28) the maximums are still as noted in my prior post, above. If using metaLUNs, the practical limit is the entire capacity of the array (the software limit is 16 exabytes, which far exceeds what can actually be put into an array). If not using metaLUNs, the limit is the size of a single RAID group (examples above).

Regards,
DGM

AranH1

2.2K Posts

June 9th, 2009 14:00

There is a limit of 16 disks per RAID group. But you can create multiple RAID groups each with one LUN using the entire usable space in the RAID group, and then create a metaLUN from all the LUNs in the RAID groups. This could result in one really big LUN, depending on the size of disk used in the RAID groups.

So through the use of metaLUNs you could create a LUN that uses all the disks in the array. But that may not be what you really need. I recommend reading through the CLARiiON best practices guide for more details on optimal configurations.

Ultan1

13 Posts

June 9th, 2009 14:00

Interesting to know.

Therefore is 16 (the amount of disks in an array) the max amount of disks allocated to a LUN?

Can I allocate more than 16 disks to a LUN?

Ultan1

13 Posts

June 9th, 2009 15:00

Thanks!

Can i create a metaLUN in a CX400 flarecode 12?

AranH1

2.2K Posts

June 9th, 2009 15:00

I don't remember. Try it :D

kelleg

4.5K Posts

June 10th, 2009 09:00

I would recommend that you review a couple of documents before you try using metaLUNs. I believe that flare release 12 was the first release that allowed the use of metaLUNs - if you right click on a LUN, one of the options is LUN Expansion - if this shows up, then you can use metaLUNs.

See the following articles on PowerLink

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H1024.1_clariion_metaluns_cncpt_wp_ldv.pdf

The following article is for release 26, your array will only support up to flare release 19, but there is a section in here that talks about metaLUNs and the proper use and configuration.

EMC CLARiiON Best Practices for Fibre Channel Storage: FLARE Release 26 Firmware Update - Best Practices Planning

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H2358_clariion_best_prac_fibre_chnl_wp_ldv.pdf


glen

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