Re: EVA Calculator? (3015 Views)
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Frequent Advisor
Matthias Rettl
Posts: 57
Registered: ‎11-19-2002
Message 1 of 14 (3,023 Views)
Accepted Solution

EVA Calculator?

Hy!
Is there any tool or document to make an exactly calculation of my eva? or is there a document or guide with informations about the internal calculations of the hsv?

for instance, i have an eva3000 with 56x72gb disks, single failure protection level. when i configure vraid5's, i get an effective useable volumespace (when i add all volumesizes as they are seen from the OS) of about 68gb per disk. 4gb is a lot of an overhead and i would like to know, WHY!

regards,
wuhte
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Trusted Contributor
florence mathon lermusi
Posts: 119
Registered: ‎06-01-2003
Message 2 of 14 (3,023 Views)

Re: EVA Calculator?

Hi,


The algorithm for reserving protected space in the EVA is to find the largest disk in your disk group (72GB), double that size (2*72=144GB) multiply the result by your protection level (1 for you) and then remove that capacity from free space and distribute it across all the disks in the disk group.

144/56=2.57GB per disk

After that you have the cost of the Vraid5 virtualization...
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Trusted Contributor
florence mathon lermusi
Posts: 119
Registered: ‎06-01-2003
Message 3 of 14 (3,023 Views)

Re: EVA Calculator?

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Honored Contributor
Uwe Zessin
Posts: 10,320
Registered: ‎02-16-2004
Message 4 of 14 (3,023 Views)

Re: EVA Calculator?

It is marketing overhead.

The size that is written on the disk drive is based on 10. The size displayed in the EVA's user interfaces (CV, SSSU) is based on 2.

When you create a virtual disk with '1 GB' you don't get room for 1,000,000,000 bytes - you get room for 2**30 = 1,073,741,824 bytes.

1,000,000,000 / 1,073,741,824 = 0.9313

The EVA reports a '72GB' disk drive with 68.36GB 'formatted capacity'.

68.36GB / 0.9313 = 73.402GB

(a StorageWorks SCSI disk drive has about 72.8GB - unfortunately I don't have a way to find out the exact block number of a FC disk drive attached to the EVA to verify that calculation)

-----

Here is some real life data:

I had initialized an EVA-3000 with one disk group, 8*72GB disk drives, protection level 0.

It reported a capacity of 546.40GB (8*68.36 = 546.88) - looks like 480MB reserved.

After I created two '5GB' VRAID-1 virtual disks, the capacity shrank to 526.31GB. That is 20GB raw capacity (2*5GB*2) for user data and 90MB reserved.

Next I created one '15GB' VRAID-5 virtual disk. The capacity shrank to 507.51GB. That is 38.75GB raw capacity (2*5GB*2 + 1*15GB*1.25) for user data and 140MB reserved.

-----

Please note that you should not max-out your EVA! It needs free space in it's disk groups to 'breathe'.

-----

I hope I got the calculations right and didn't just look like a fool...
Corrections welcome.
.
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Honored Contributor
Peter Mattei
Posts: 1,140
Registered: ‎06-17-2001
Message 5 of 14 (3,023 Views)

Re: EVA Calculator?

Find attached the EVA Sizer written by Martin Casaulta. It is an unofficial tool but can help in planning EVAs either standalone or CAed.
I use it every time I plan a configuration!

Enjoy
Peter
I love storage
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Occasional Visitor
Degafait
Posts: 1
Registered: ‎09-13-2004
Message 6 of 14 (3,023 Views)

Re: EVA Calculator?

I am also interesting in your calculator. But i Can't open your file.
Could you repost your document wihout Microsoft Word password ?
Thanks in advance
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Honored Contributor
Peter Mattei
Posts: 1,140
Registered: ‎06-17-2001
Message 7 of 14 (3,023 Views)

Re: EVA Calculator?

First of all, it is a ZIP file without any password containing an Excel spreadsheet ready to use!

I attach the latest version 3.2.1 here!

Cheers
Peter
I love storage
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Frequent Advisor
Matthias Rettl
Posts: 57
Registered: ‎11-19-2002
Message 8 of 14 (3,023 Views)

Re: EVA Calculator?

Thanx for posting the new version! What changes where made to the 3.2.0? Is the new licensing model of SOM already implemented?

kind regards,
wuhte
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Honored Contributor
Peter Mattei
Posts: 1,140
Registered: ‎06-17-2001
Message 9 of 14 (3,023 Views)

Re: EVA Calculator?

The changes are minor:

To fix an internationalization problem (Excel versions in french, german, etc.) in the area of the export function!

Well, under SOM LTU the sizer shows the raw space an EVA provides. You can decide yourself how you want to license!
With the new SOM licensing you can either licencse one or multiple 1TB LTUs or unlimited LTU per EVA.

Hint:
For both the EVA3000 and the EVA5000 5x 1TB LTU is the same price as the unlimited LTU.

Cheers
Peter
I love storage
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Advisor
Douglas Spooner
Posts: 18
Registered: ‎10-13-2005
Message 10 of 14 (3,023 Views)

Re: EVA Calculator?

This tool is really very handy. Its made my life so much easier!

You should win an award!
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Honored Contributor
Peter Mattei
Posts: 1,140
Registered: ‎06-17-2001
Message 11 of 14 (3,015 Views)

Re: EVA Calculator?

In the mean time HP included an EVA sizer into the official SWD sizer application that can be downloaded from

http://www.hp.com/go/nsssizer

Beside EVA you can size XP, SAN, NAS and even backup environments.

Check it out!

Cheers
Peter
I love storage
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Frequent Advisor
ReynierPM
Posts: 66
Registered: ‎04-03-2010
Message 12 of 14 (3,015 Views)

Re: EVA Calculator?

Hi, I'm trying to use this amazing tool but have some problems and doubts.

First the problem: when I open the workbook in Excel 2010 this error appear on column I (Neto Capacity GB | TB) with this formule (=SUM($AE5:$AG5)*#NAME?/100) as you can see this #NAME? cause not value when I try to calculate the capacity.

Second the doubt: I'm plannig to buy a EVA8400 with 7 full capacity disk enclosures. The configuration will be then 2C7D. The disk are FC and have 600 GB raw capacity. What Virtual Raid Level Mix field/column means? I mean wich value I need to enter there a 100 or minus?

Thanks in advance
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本科生
宋明哲
Posts: 8,055
Registered: ‎10-18-2004
Message 13 of 14 (3,015 Views)

Re: EVA Calculator?

Can this excel work well in Excel 2010? When I open it. Excel report Error and Must fix it; After fixed, the sheet doesn't work;
I'm back, water king
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Frequent Advisor
ReynierPM
Posts: 66
Registered: ‎04-03-2010
Message 14 of 14 (3,015 Views)

Re: EVA Calculator?

Hi every:
I'm trying to build a VRAID5 Excel Planner for my interal use and also to share with you but first need to understand how I can calculate this in order to get the tool working. For example I need to build a VRAID5 with 90TB with storage with a EVA8400 and 2C. Can any point me in the right direction?
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