ONTAP Discussions

## Re: NetApp Usable Space Calculator

24HDD-2Parity-2Spare-1root volume diks=19HDD

Real capacity of 900gb about 850gb

19*850=16150gb

16150gb-10%wafl=14535gb

14535gb-3% aggr reserve = 14098.95

Really root volume  takes 250 gigabytes, but I deducted the entire disc. Nevertheless, the overall volume I still get more.May be I do something wrong?

## Re: NetApp Usable Space Calculator

well i think you got some issues using the calc

i always use 0 disk for allocated root disk, since i put the root-vol into the same aggr like the data for 7-mode systems

the raidgroup size should the match "No of Disk" minus " "Spare disks" - always having the max rgsize in mind (SAS = 28, SATA=20)

hope that give you a better understanding

best andreas

## Re: NetApp Usable Space Calculator

Hello ALEKSEYSVECHNIKOV

A few best practices on root volume.
Root volume contains all configurations files (ONTAP Files). It is always preferred to separate the root volume from the data volumes on the filer. For optimal management, it is better to restrict the root volume to just 2 disks (minimum required for a RAID-4 parity group). This enables faster reconstruction times in case of a disk failure on the root volume

with your hand calculation

24HDD-2Parity-2Spare-1root volume diks=19HDD
Real capacity of 900gb about 850gb
19*850=16150gb
16150gb-10%wafl=14535gb
14535gb-3% aggr reserve = 14098.95

This will be how I will calculate / size it.

Total of 24 HDD
2 for root volume
2 for spares

we lose 4 disks and 20 remain. So RG size can be 20
With a RG size of 20 we lose 2 disks for parity so net usable disks becomes 18

900 GB SAS disk's right sized approx value is 837 GB
18 x 837 = 15066
15066 - 10% WAFL = 13559.4
13559.4 - 3% AGGR = 13152.61
then if you need volume reserve you need to subtract 20% from 13152.61

Hope this gives an idea ?

## Re: NetApp Usable Space Calculator

Hi, why some disk size are not considered? For instance, the 600g FC disk drives.

Thanks

## Re: NetApp Usable Space Calculator

Hello Lorenzo.Conti

600 GB SAS/FC - This means there is both SAS/FC available for 600 GB, but they right-size down to the same usable capacity

Murugappan

## Re: NetApp Usable Space Calculator

hi guys,

first of all - great tool i use quite often - thanks!

my question:

what about the upcoming feature for "disk partitioning"  - will this be integrated within the tool so we get better results for smaller boxes? e.g. 25xx?

thanks

andreas

## Re: NetApp Usable Space Calculator

First of all, great tool, thanks for writing it.

Now, my question.  I'm new to the NetApp world, coming from an Equallogic world.  With Equallogic, figuring out usable disk space is really easy since it shows you in the management GUI.  That said, they don't offer as many options for disk layout as NetApp does, which is where my confusion comes from sometimes.  It seems like I lose alot of usable disk space very quickly with Netapp depending on how pools/aggregates/volumes are configured.  And when you throw in splitting disks to different controllers, you can lose even more space.
I've used the tool a few times, and I have a few questions/suggestions:
1. Add help text for each field to describe what it's for or what it is showing.  This might help people that are new to NetApp.
2. Is the tool designed to show usable space on just a single shelf, or for an array with multiple shelves?
3. Is the app assuming that disks are assigned to just a single controller?
4. Is the app assuming that all disks are assigned to just a single aggregate?  I'm assuming so since it's asking for the number of disks assigned to the root volume, which suggests a single aggregate with multiple volumes?
5. Does the app assume that there is just a two volumes, one for root, and the other needs.  I ask since volume reserve only kick in AFTER you've created a volume if I understand correctly?  And in that case, under usable space, is it showing the data for the second volume, or just raw disk space.  Should there be fields to show the total aggregate space and the total volume space?
6. Assuming that the app is splitting the aggregate in to two volumes, if you change the number of disks allocated for root volume, does it then adjust to show data for a single volume?
7. Does the Raid Group Size Estimater actually change the amount of disk space shown, or is it just to show recommended values for RG size?
I may have more questions later as I dig in to this more.
Thanks,
David

## Re: NetApp Usable Space Calculator

Replying to my own post, I've done some more testing with the app and have a few more suggestions/questions:

• Under Usable space, show the raw and right size capacity per disk so that someone can see how much they lose per disk.
• For #2 below, since you can put in more than 24 drives, that makes me think now that it is aware of multiple shelves.  That said, does the app put the root aggregate/volume on one shelf and not on all shelves?
• For #5 below, wanted to change that to also ask if the app is assuming two aggregates, or a single aggregate with two volumes.
• for #7, I think I figured it out.  Could you also have it show the number and size of aggregates?
• For Spare Disks, when the number of Total Disks is high, is the program using X spare disks per 30 drives, or some other value.  Would it make sense to add a field to ask that?
• Under Usable Space, would it be possible to show how many disks are used for spares, DP, etc?  That would help people visualize how many disks are used.  For example: show that X disks are used for Spares for every Y # of disks;  Show that 2 disks are used for DP for X number of disks in the RG Size.

Thanks again,

Dave

@dfields42 wrote:

First of all, great tool, thanks for writing it.

Now, my question.  I'm new to the NetApp world, coming from an Equallogic world.  With Equallogic, figuring out usable disk space is really easy since it shows you in the management GUI.  That said, they don't offer as many options for disk layout as NetApp does, which is where my confusion comes from sometimes.  It seems like I lose alot of usable disk space very quickly with Netapp depending on how pools/aggregates/volumes are configured.  And when you throw in splitting disks to different controllers, you can lose even more space.
I've used the tool a few times, and I have a few questions/suggestions:
1. Add help text for each field to describe what it's for or what it is showing.  This might help people that are new to NetApp.
2. Is the tool designed to show usable space on just a single shelf, or for an array with multiple shelves?
3. Is the app assuming that disks are assigned to just a single controller?
4. Is the app assuming that all disks are assigned to just a single aggregate?  I'm assuming so since it's asking for the number of disks assigned to the root volume, which suggests a single aggregate with multiple volumes?
5. Does the app assume that there is just a two volumes, one for root, and the other needs.  I ask since volume reserve only kick in AFTER you've created a volume if I understand correctly?  And in that case, under usable space, is it showing the data for the second volume, or just raw disk space.  Should there be fields to show the total aggregate space and the total volume space?
6. Assuming that the app is splitting the aggregate in to two volumes, if you change the number of disks allocated for root volume, does it then adjust to show data for a single volume?
7. Does the Raid Group Size Estimater actually change the amount of disk space shown, or is it just to show recommended values for RG size?
I may have more questions later as I dig in to this more.
Thanks,
David

## Re: NetApp Usable Space Calculator

1.Add help text for each field to describe what it's for or what it is showing.  This might help people that are new to NetApp.

Great Suggestion. I will try to make it in the next version

2.Is the tool designed to show usable space on just a single shelf, or for an array with multiple shelves?

Multiple shelves. Think interms of no of disks.
3.Is the app assuming that disks are assigned to just a single controller?
Yes. All I am trying to show is an approx space if we buy "n" no of disks

4.Is the app assuming that all disks are assigned to just a single aggregate?  I'm assuming so since it's asking for the number of disks assigned to the root volume, which suggests a single aggregate with multiple volumes?
Yes single aggregate.
5.Does the app assume that there is just a two volumes, one for root, and the other needs.  I ask since volume reserve only kick in AFTER you've created a volume if I understand correctly?  And in that case, under usable space, is it showing the data for the second volume, or just raw disk space.  Should there be fields to show the total aggregate space and the total volume space?

I am just trying to make this very simple. I am deducting the root vol disks either 2 or 3 which leaves with one aggregate (basically for other needs).
A few best practices on root volume.
Root volume contains all configurations files (ONTAP Files). It is always preferred to separate the root volume from the data volumes on the filer. For optimal management, it is better to restrict the root volume to just 2 disks (minimum required for a RAID-4 parity group). This enables faster reconstruction times in case of a disk failure on the root volume

6.Assuming that the app is splitting the aggregate in to two volumes, if you change the number of disks allocated for root volume, does it then adjust to show data for a single volume

Yes..single aggregate.

7.Does the Raid Group Size Estimater actually change the amount of disk space shown, or is it just to show recommended values for RG size?
No effect on the disk space. Just shows recommended values. Fill the top 3 rows (before the separator line)

## Re: NetApp Usable Space Calculator

•Under Usable space, show the raw and right size capacity per disk so that someone can see how much they lose per disk.
This is available in NetApp charts - https://library.netapp.com/ecmdocs/ECMP1196912/html/GUID-5D3F3F2D-A153-49D3-9858-04C30B3C7E74.html

•For #2 below, since you can put in more than 24 drives, that makes me think now that it is aware of multiple shelves. That said, does the app put the root aggregate/volume on one shelf and not on all shelves?

Basically we are allocating 3 disks for root volume. This app is not tied to controller/shelves etc.

•For #5 below, wanted to change that to also ask if the app is assuming two aggregates, or a single aggregate with two volumes.
The final space shown is for a single aggregate

•for #7, I think I figured it out. Could you also have it show the number and size of aggregates?
I will try

•For Spare Disks, when the number of Total Disks is high, is the program using X spare disks per 30 drives, or some other value. Would it make sense to add a field to ask that?
I leave the judgement to the user on how much quantity he enters in this field.

•Under Usable Space, would it be possible to show how many disks are used for spares, DP, etc? That would help people visualize how many disks are used. For example: show that X disks are used for Spares for every Y # of disks; Show that 2 disks are used for DP for X number of disks in the RG Size.
I will try to incorporate this as well.

## Re: NetApp Usable Space Calculator

The tool is great and I've read through and understand the formulas behind it, however, the "official" Netapp data presented on the Hardware Universe is different to what we get with this tool. With this in mind I have a few questions...

Which can we expect to see (or which is closest) in actual deployment, NUSC or HWU?

Does anyone know what is being used to calculate the figures seen in HWU and why they differ from formula used in NUSC (Mktg Capacity / Physical / Right Sized vs Base 10 / Base 2 / Right-sized)?

With NL-SAS Disks are they subject to the same checksum rules as SATA and subsequent right-sizing (ie. is the sector size the same as SAS or SATA)?

Any plans to update the tool to include new disk szings since last release?

## Re: NetApp Usable Space Calculator

You need to add 400 GB SSD Drives to your mix. Nice Work. I like the recommended section you put in as well.

Phililp

## Re: NetApp Usable Space Calculator

Nice Tool. do you have updated version.

For the disk type, 600GB SAS - it doesnot show correctly. Please verify at your end. Thanks.

## Re: NetApp Usable Space Calculator

Just following up on this thread. Looking for a way to calculate aggr with 1.8 SAS, 4TB NL SAS, 6TB NL SAS, and ADP flash pools. Great tool! I would love to see a current version. 🙂

## Re: NetApp Usable Space Calculator

Thank you for the tool.

Is there an updated version of this including bigger SSD drives?

## Re: NetApp Usable Space Calculator

Is there a new version? Do you accept donations? I would definitely help fund your work on keeping this tool up-to-date?

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