MD1000 DAS showing 46gig available instead of 2TB

[daunce]

Hi all.

We've set up an ESX3.5 box, using a DELL 2950 with PERC6 attached to an MD1000 with 4x750's in raid 5.

From within VI client, we can add the local disks all ok, and it picked up the MD1000 showing 2TB available, but it says 46GB available. We've (fast) initiialised the das, so there isn't any data on there. Just not sure why it's not giving us the full amount it can see.

This server has 3.5 with no updates, although we've tried it on another box with 3.5.0, 120512.

Any ideas? much appreciated.

daunce

[weinstein5]

The issue is the is te size of the RAID set a RAID 5 of 4 750 GB will equal 2,25 TB which is too large for ESX to recognize - try setting up to mirroered sets - you will have 2 750 GB datastores -

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[daunce]

I found some docs that say the max VMFS volume is 64TB.. but further reading reveals the single largest volume is 2TB, but then you can add extents of 2TB, up to a total of 64TB. Seems a bit misleading.

The weird thing is that if the raid set is larger than 2TB, whatever is left over past the 2TB limit, it says that is the space available, and is actually how much space is assigned.

Thanks for the suggestion, but we're not after a mirrored setup. We'd prefer to use more disk, than a complete mirror for this project.

We will create 2 raid sets, and we may look into using extents.. will need to check the pitfalls of that first though.

-daunce

[mcowger]

He's not talking about mirrored setups - he talking about 2 datastores.

--Matt

[KellyOlivier]

Most advise against using extents, and it is a recommended best practice to not use them unless temporairly expanding a datastore. Extents rely on the original disk set so if your original disk set fails the entire datastore will fail. Others can chime in on other reasons.

[daunce]

Thanks Kelly. I am keen to here people's experiences and advise on extents.

[mcowger]

Do a search on this - you will find most (like me) avoid them like the plague.

--Matt