Celerra Manager v 5.5 - Help creating new iscsi LUN

Question

First of all I am rather new at using the Celerra Manager. I thought I knew the steps for creating an iscsi lun, but when I try to create the lun, I get a message that "VersionSet_OutofSpace!"

I created a new filesystem then attempted to create a new LUN using the new filesystem. I must be missing a step.

Is there a way to see if perhaps Checkpoints are taking up all of the available space and may need to be removed to free up space for my iscsi LUN?

Sorry for the basic question. If you can just refer me to some online documentation, that would be great as well.

Duane_Olson · Accepted Answer

Unfortunately, you cannot create an iSCSI LUN exactly equal to the filesystem size. The rule of thumb I have used successfully is to create the iSCSI LUN to the nearest 100MB of the filesystem size..

For instance, the filesystem is 102400MB in size. You can create a LUN of 102000 MB in size. You can play with this and get it to the maximum size, but its trial and error.

The reason for this is the way the iSCSI LUN is created in the filesystem. Since the filesystem is formated to 8k file block size, each 8k, or portion of 8k in your size consumes 8k of space. A 10k LUN will consume 16K of space. A 16K LUN will consume only 16K, but a 17K will consume 24K...

fzilz · Answer

When creating the lun the filesystem selected shows the mb of the filesystem, I am just typing in the same number. I will try typing in a smaller number to see if it makes any difference.

Yes, up until now, most all of my questions have been answered by the help options on the celerra manager.

Thank you.

fzilz · Answer

Thank you, that was what I was missing. After reading your post, I remember that from my training at the installation of our NS 352, but had forgotten all about it.

SO, after creating the LUN 100 mb smaller than the filesystem. The lun was created. Then I extended it to maximum (it allowed 90 mb).

Thanks again.

Rainer_EMC · Answer

actually the reason that you cannot create an ISCSI LUN exactly as big as the available free space in your file system is that the ISCSI LUN itself gets stored as a file and needs some metadata (direct and indirect blocks) to tell the file system which data blocks belong to the LUN. Similar to the NTFS MFT table

This is typcially in the less than 1% range.

Same thing would happen if you tried to create a normal file of that size.

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Celerra Manager v 5.5 - Help creating new iscsi LUN

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