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Calculating space requirements on an EVA

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Calculating space requirements on an EVA

I am trying to estimate how much of the available space on an EVA I can use before I hit the occupancy threshold. And conversely, if I add disks to a disk group, how can I figure out my now usable space in the group.

Any have a tool to provide that information?

Thanks,

Dave Harrold
4 REPLIES
Steven Clementi
Honored Contributor

Re: Calculating space requirements on an EVA

David:


The calculation should be rather simple. If your threshold is set to 50% and you have 2TB of available storage, when you have allocated 1.001TB, you will be passed the threshold and therefore, will be in a warning condition in Command View EVA.

Command View EVA will show you the actual usable space, I suspect that you would like to be able to calculate the values in the case that you do not have access to your Storage Management Server.

As long as you do not mix disks, you can estimate the @ available space as long as you know the current available space.

Assuming you have 1TB available nd you add in 8 more 72GB drives... you've added 576 GB total. So long as you don't change protection levels or make any new vdisks or de-commission any old vdisks, you will have @1.576TB available for usage(RAID0)(RAID1 and RAID5 would ovbiously be less, @50% less for RAID1 and @1 disk size less for RAID5). There is, of course, some over head and it would be a closer assumption if you used a value of 70GB or 68GB instead of 72GB.

As far as a tool, I am aware of an EVA sizing tool, but do not have access to the most current one. Also, I am not sure if it is available to the general public nor do i know if it can take into consideration already utilized storage, but knowing the numbers and factors you can probably make your own quick excel sheet to do the math for you.


Steven
Steven Clementi
HP Master ASE, Storage and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5)
RHCE
NPP3 (Nutanix Platform Professional)
Uwe Zessin
Honored Contributor

Re: Calculating space requirements on an EVA

> There is, of course, some over head and
> it would be a closer assumption if you
> used a value of 70GB or 68GB instead of 72GB.

It's not 'overhead' - it's the difference between 'hardware GB' and 'software GB'. The drive vendors public their data as 'hardware GB' on base(10). Command View EVA displays 'software GB'.

E.g.:
the "BD1465822C" FC disk has 286749488 blocks.

286749488 blocks * 512 byte/block = 146815737856 bytes (HW)

146.81GB /1024*1000/1024*1000/1024*1000 = 136.727GB (SW)


Now, watch out for the 'sizers'. Some of them run everything in HWTB. Some formulars reserve a fixed 10% space in your disk group.
.
Uwe Zessin
Honored Contributor

Re: Calculating space requirements on an EVA

> There is, of course, some over head and
> it would be a closer assumption if you
> used a value of 70GB or 68GB instead of 72GB.

It's not 'overhead' - it's the difference between 'hardware GB' and 'software GB'. The drive vendors public their data as 'hardware GB' on base(10). Command View EVA displays 'software GB'.

E.g.:
the "BD1465822C" FC disk has 286749488 blocks.

286749488 blocks * 512 byte/block = 146815737856 bytes (HW)

146.81GB /1024*1000/1024*1000/1024*1000 = 136.727GB (SW)

Output from SSSU:
>Formatted_Capacity : 136.73 GB


Now, watch out for the 'sizers'. Some of them run everything in HWTB. Some formulars reserve a fixed 10% space in your disk group.
.
Luk Vandenbussche
Honored Contributor
Solution

Re: Calculating space requirements on an EVA

Hi,

There is a sizing tool voor EVA.

Downloadable through

http://h30144.www3.hp.com/