hp msa 2040 expand space

[ewjimy]

Hi, I'm a complete newbie to hp msa 2040, please help me figure out the current free space on the storage and how can I add space to my main pool? I am attaching screenshots. https://imgur.com/a/N0b6y6A

[SUBHAJIT KHANBARMAN_1]

@ewjimy 

MSA 2040 is 4th Generation array in HPE MSA family which can be used as Linear and Virtual. This is exactly done for your system as well.

Linear means Thick Volume or Fully allocated Space

Virtual means Thin Volume or space will get allocated as in when host require to write new data. Also space get reduced or reclaimed when data gets deleted at the host end.

In your setup, you have Pool A which is configured as Virtual and this is owning by Controller A. On the other side, you have Vdisk named Vol2 which is configured as Linear and this is owning by Controller B.

First coming to Linear part
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Your total Linear Storage space = (Reserved + Allocated + unallocated) = 16.0TB but usable space 11.9TB only

(Note: Reserved is nothing but space that gets consumed due to RAID parity and metadata. This space can't be used for user data)

Vol2 is vdisk whose size is 11.9TB and 1 Volume created from this vdisk named Vol2_v0001 whose size 11.8TB. It means still some space left on the vdisk which is nothing but free space shows as 90.2GB

It looks like this Volume not presented to any hosts so entire 11.8TB is unused or blank from host perspective but from array perspective entire 11.8TB is allocated because this is Thick Volume.

So if you want to increase space of vdisk Vol2 then you have to add more drives with this vdisk. Also you can add more drives and create separate vdisks as well.

Now coming to Virtual Part
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Here we have Virtual Pool concept and that is Pool A whose total size = (Reserved + Allocated + unallocated) = 24.0TB but usable space 19.9TB only

(Note: Reserved is nothing but space that gets consumed due to RAID parity and metadata. This space can't be used for user data)

Here Volume gets created from Pool instead of vdisk which you have seen in Linear concept but base infrastructure same like with physical drives we create Virtual Disk groups(VDG) like in Linear concept with drives we create Vdisk.

Here VDG named dgA01 whose size 19.9TB

1 Volume created from Pool A named Vol0001 whose size 19.8TB but here not entire space fully allocated as this is Thin Volume. Here actual data allocated 12.5TB which means almost 7.3TB space unallocated or free both from VDG and Pool perspective.

Now if you want to increase Pool A size then you need to create a separate VDG with required drives and add this new VDG to Pool A as existing VDG expansion not allowed like Linear array Vdisk expansion.

Hope this helps!
Regards
Subhajit

I am an HPE employee

If you feel this was helpful please click the KUDOS! thumb below!

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[ewjimy]

Thank you very much for your answer. So can I expand my virtual pool by decreasing the linear pool? If so, could you please explain in detail how to do this in my case?

[SUBHAJIT KHANBARMAN_1]

@ewjimy 

Just delete volume named Vol2_v0001 and then vdisk named Vol2. All 8 drives associated with Vol2 will become available drive.

Then you create new Virtual Disk Group (VDG) with these 8 drives but please note the existing VDG named dgA01 got created with 12 drives and in RAID6. So if you want to add this new VDG to same Pool A then I would suggest to match the no of drives and RAID as well. This is important from performance perspective but not restricted. You can create new VDG with 8 drives and add it to Pool A as well.

You can also create new VDG and add it to Pool B as well.

Hope this helps!
Regards
Subhajit

I am an HPE employee

If you feel this was helpful please click the KUDOS! thumb below!

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