P4000 Data Utilization

[David Strydom]

Hi there,

I have a situation where we thin provision a volume for an Esx4 server. 400GB, the disk has used about 390GB. In Lefthand Mgt Console it is reporting the following.
Size: 400GB
Replication Level: 2-Way
Provisioned Space: 788GB
Utilization: 99%

Why has the 400GB volume been provisioned 788GB.

Thanks
David

P.S.This thread has been moved from Storage Area Networks (SAN) (Small and Medium Business)  to HP StoreVirtual / HP LeftHand Storage- HP Forums Moderator

[Uwe Zessin]

because you have configured 2-Way replication. Each data block is stored two times in the management group.

You wrote: "the disk has used about 390GB"

788/2 = 394 ... that matches quite well, doesn't it?

[David Strydom]

Okay, kind of makes sense but I am just trying to understand this.

Basically if you look at the cluster it reflects the Disk Space usage relative to only 1 node as they are in a cluster. For example we have a 2 X 4TB SAN and all the info for a cluster is shown as 4TB not 8TB.

But you are saying on the volumes it reflects the space utilised over both nodes.

Seems a bit strange that.

Cheers
David

[Uwe Zessin]

I don't have access to a P4000 right now to check. Can you take a set of screen shots (simple .JPG, please), put them in a .ZIP file and attach to another response?

[David Strydom]

Okay,

attached is cluster view.jpg and volume view.jpg.

You will see the provisioned for volumes in cluster view is 1139GB which is exactly right if you add up what the provisioned space under each volume is. But total size is only showing 4TB.

Cheers
David

[Matthew S. Luth · Accepted solution]

Hi David,

All LUNs that you define on your cluster as 2-way replicated will use 2x of your raw storage pool because that data is mirrored.

If you'll go to the cluster level and look at the "Volume Use" tab, it becomes a little clearer.

Size = what you present to your server

Provisioned Space = how much physical storage is actually being used by that lun currently

Provisionable Space = how much total space could be allocated if you actually filled the volume

Used Space = how much of the "Provisioned Space" (currently used) has been filled with actual data

Utilization = what percentage of "Provisioned Space" has been filled with actual data

It still confuses me when I look at it but it makes sense since you could have volumes with no replication as well as volumes with 3-way replication all using varying amounts of physical storage. No replication would result in an essentially one-to-one perspective.

Hope this helps.
Matt

[David Strydom]

That makes more sense now. Thanks for the help.

[Mark...]

Hi
Whilst this statement is sort of correct:
"Used Space = how much of the "Provisioned Space" (currently used) has been filled with actual data"
In the case of thin provisioning with Lefthand products if data is deleted then the space IS NOT recovered and the used space will not reflect the total amount of data - unless you fill it up with data again of course:)
Mark...

[Urimuqi]

do you have detail materials for me to learn?