HPE Storage Users Group

Hello All,

Is there any math behind calculating the usable space in 3PAR? I know showspace does show results depending on raid level. However, I am looking to do the calculations for a new 3PAR array which needs to be bought in a month or so. I need to find out the usable space from total RAW capacity we are buying from HP.

For e.g. 100 TB -- Total RAW capacity

What would be usable for RAID 5?

Thanks,
G Kapoor

I’m not aware of how to calculate this, but Im able to provide you with real numbers from a running 3Par system with approx 80 Tb raw disk capacity, giving my aprox 54 Tb usable space.


We have a new 3par dual 7400 controller witch is equipped with 96 FC 900Gb 10K HDs + 16 SSD 200 Gb HDs (6 cages + controller cage)
simple calculated total raw FC+SSD capacity is 96*900+16*200 = 89.600 Gb
In 3Par GUI FC+SSD capacity is calculated into 81.584.00 GiB usable space witch is the true RAW capacity of the disks (900 Gb disk holds 819 Gb formatted data).
Below Im only talking about the FC numbers excluding the SSD's.

when formatted by 3Par it shows that my NL HD have a raw capacity of 78.624 GiB of storage.

From this my system takes approx. 5% to system, spare drives ect., and additional 2% to copy drive (remote copy) - if not using remote copy I assume you don't need to calculate with this 2-3% copy space.

Left is approx. 72 Tb usable space

Beside these approx. 7% it all depend on the type of raid used. raid 5 uses 3 data + 1 parity and raid 6 uses 6 data + 2 parity (according to my GUI) - witch should translate into 25% loss due to raid parity - RAID 6 should in theory have a larger overhead but my GUI shows the above mentioned overhead.

all in all I have created approx. 30 LUNS totaling at about 186 Tb Thin provisioned and these holds approx. 41 Tb data.
since my 72 Tb is the usable space without raid, this will be approx. 54 Tb usable SPACES in total.

I’m coming from a Netapp of similar size (84 x FC 10/15 K HDs), and to my experience the 3Par is by far the best product. CPU util is far lower and
Netapp give less usable space for the same amount of raw storage and is less flexible - since you have to assign disks to aggregates and a disk is owned by a controller - here all disks belongs by default to 1 big pool owned by any controller, from witch your CPG's automatically takes what is needed.

My server performance HAS gained significant and client wait time HAS been reduced.
We are very happy by the switch from Netapp to 3Par - much simpler to maintain and daily tasks can be dealt with in-house instead of consultans - it takes aprox 1 day and you can manage it easyly.

going from 3½" to 2½" system have also lowered the power requirement to half and the cooling as well - I belive this would have been the same with Netapp (they are using the same HW OEM supplier - cages are visually identical beside the color

hope you can use this for calculating your needs. if you are about to get a quote for a new system, then make shure there will be space for extra HDs in - cages without disks does not cost mutch to add from start - in my case I have 6 cages and 1 controller cage (7x24 HDs) - leaving space for 168 HDs - although only using 112 HDs are assigned by now.

If you're a HP Partner you can download the HP Storage Sizing tool here:
http://h71028.www7.hp.com/enterprise/us ... tools.html

You will need a licence but there are instructions on how to obtain. It also will calulate useable space and (in some cases IOPS) for all other HP storage. A very useful tool.

Also you could try a google search for HP 3PAR Ninja Transformer or Ninja sizer -they are less offical HP XL based tools that can do the same thing.

Thank you Guys! That is helpful

Hi every one.

I have a question about usable space too.

I Have a 3PAR 7400 with two nodes and this disks.

144HDD x 300GB 15k
40HDD x 900GB 10k
8HDD x 200GB SSD

When I get into the Management Console I can see the next data.

The system reports 116,728.000GiB as total RAW space.
The 31% is Allocated and 69% is free.
The 88% of the allocated space is for CPGs Volumes
The 11% of the allocated space is for system spare and
The other 1% of the allocated space is for system internal

Also I have this information, is a CSV file.

,Total: 116728.000 GiB (100.00%)
,,Allocated: 36678.000 GiB (31.42%)
,,,Volumes: 32228.000 GiB (27.61%)
,,,,Non-CPGs: 0.000 GiB (0.00%)
,,,,,User: 0.000 GiB (0.00%)
,,,,,Snapshot: 0.000 GiB (0.00%)
,,,,,Admin: 0.000 GiB (0.00%)
,,,,CPGs : 32228.000 GiB (27.61%)
,,,,,User: 31978.000 GiB (27.40%)
,,,,,,Used: 30470.000 GiB (26.10%)
,,,,,,Unused: 1508.000 GiB (1.29%)
,,,,,Snapshot: 154.000 GiB (0.13%)
,,,,,,Used: 1.000 GiB (0.00%)
,,,,,,Unused: 153.000 GiB (0.13%)
,,,,,Admin: 96.000 GiB (0.08%)
,,,,,,Used: 5.250 GiB (0.00%)
,,,,,,Unused: 90.750 GiB (0.08%)
,,,,Unmapped: 0.000 GiB (0.00%)
,,,System: 4450.000 GiB (3.81%)
,,,,Internal: 311.000 GiB (0.27%)
,,,,Spare: 4139.000 GiB (3.55%)
,,,,,Used: 0.000 GiB (0.00%)
,,,,,Unused: 4139.000 GiB (3.55%)
,,Free: 80050.000 GiB (68.58%)
,,,Initialized: 80050.000 GiB (68.58%)
,,,Uninitialized: 0.000 GiB (0.00%)
,,Failed: 0.000 GiB (0.00%)
,Fast Class: 71928.000 GiB (100.00%)
,,Allocated: 29493.000 GiB (41.00%)
,,,Volumes: 25228.000 GiB (35.07%)
,,,,Non-CPGs: 0.000 GiB (0.00%)
,,,,,User: 0.000 GiB (0.00%)
,,,,,Snapshot: 0.000 GiB (0.00%)
,,,,,Admin: 0.000 GiB (0.00%)
,,,,CPGs : 25228.000 GiB (35.07%)
,,,,,User: 25064.000 GiB (34.85%)
,,,,,,Used: 23588.000 GiB (32.79%)
,,,,,,Unused: 1476.000 GiB (2.05%)
,,,,,Snapshot: 92.000 GiB (0.13%)
,,,,,,Used: 0.000 GiB (0.00%)
,,,,,,Unused: 92.000 GiB (0.13%)
,,,,,Admin: 72.000 GiB (0.10%)
,,,,,,Used: 5.250 GiB (0.01%)
,,,,,,Unused: 66.750 GiB (0.09%)
,,,,Unmapped: 0.000 GiB (0.00%)
,,,System: 4265.000 GiB (5.93%)
,,,,Internal: 311.000 GiB (0.43%)
,,,,Spare: 3954.000 GiB (5.50%)
,,,,,Used: 0.000 GiB (0.00%)
,,,,,Unused: 3954.000 GiB (5.50%)
,,Free: 42435.000 GiB (59.00%)
,,,Initialized: 42435.000 GiB (59.00%)
,,,Uninitialized: 0.000 GiB (0.00%)
,,Failed: 0.000 GiB (0.00%)
,Near Line: 43320.000 GiB (100.00%)
,,Allocated: 6960.000 GiB (16.07%)
,,,Volumes: 6960.000 GiB (16.07%)
,,,,Non-CPGs: 0.000 GiB (0.00%)
,,,,,User: 0.000 GiB (0.00%)
,,,,,Snapshot: 0.000 GiB (0.00%)
,,,,,Admin: 0.000 GiB (0.00%)
,,,,CPGs : 6960.000 GiB (16.07%)
,,,,,User: 6914.000 GiB (15.96%)
,,,,,,Used: 6882.000 GiB (15.89%)
,,,,,,Unused: 32.000 GiB (0.07%)
,,,,,Snapshot: 46.000 GiB (0.11%)
,,,,,,Used: 0.000 GiB (0.00%)
,,,,,,Unused: 46.000 GiB (0.11%)
,,,,,Admin: 0.000 GiB (0.00%)
,,,,,,Used: 0.000 GiB (0.00%)
,,,,,,Unused: 0.000 GiB (0.00%)
,,,,Unmapped: 0.000 GiB (0.00%)
,,,System: 0.000 GiB (0.00%)
,,,,Internal: 0.000 GiB (0.00%)
,,,,Spare: 0.000 GiB (0.00%)
,,,,,Used: 0.000 GiB (0.00%)
,,,,,Unused: 0.000 GiB (0.00%)
,,Free: 36360.000 GiB (83.93%)
,,,Initialized: 36360.000 GiB (83.93%)
,,,Uninitialized: 0.000 GiB (0.00%)
,,Failed: 0.000 GiB (0.00%)
,SSD: 1480.000 GiB (100.00%)
,,Allocated: 225.000 GiB (15.20%)
,,,Volumes: 40.000 GiB (2.70%)
,,,,Non-CPGs: 0.000 GiB (0.00%)
,,,,,User: 0.000 GiB (0.00%)
,,,,,Snapshot: 0.000 GiB (0.00%)
,,,,,Admin: 0.000 GiB (0.00%)
,,,,CPGs : 40.000 GiB (2.70%)
,,,,,User: 0.000 GiB (0.00%)
,,,,,,Used: 0.000 GiB (0.00%)
,,,,,,Unused: 0.000 GiB (0.00%)
,,,,,Snapshot: 16.000 GiB (1.08%)
,,,,,,Used: 1.000 GiB (0.07%)
,,,,,,Unused: 15.000 GiB (1.01%)
,,,,,Admin: 24.000 GiB (1.62%)
,,,,,,Used: 0.000 GiB (0.00%)
,,,,,,Unused: 24.000 GiB (1.62%)
,,,,Unmapped: 0.000 GiB (0.00%)
,,,System: 185.000 GiB (12.50%)
,,,,Internal: 0.000 GiB (0.00%)
,,,,Spare: 185.000 GiB (12.50%)
,,,,,Used: 0.000 GiB (0.00%)
,,,,,Unused: 185.000 GiB (12.50%)
,,Free: 1255.000 GiB (84.80%)
,,,Initialized: 1255.000 GiB (84.80%)
,,,Uninitialized: 0.000 GiB (0.00%)
,,Failed: 0.000 GiB (0.00%)

This is my question, Is there a quick way to know what is the free usable space in all the system?

Thanks...

You can use showspace command to check that.

e.g. showspace -p devtype FC (would show usable space considering raid 1)

showspace -t r5 -p devtype FC (would show usable space counting RAID 5)

try same for all device types.

Thanks,
G Kapoor

Ok I will try it.

Thanks gkapoor

Hi, I have a 7200 for Demo. 1 enclosure 8 disks x 450Gb. 4 disk x cage.

Created a R1 CPG and then tried to create a FPVV of 100Gb but the system says I don't have enought space. Then I created a 1Tb TPVV without problem. Any idea of what I'm missing or missunderstanding about 3PAR's space management.

Thanks for your help.

marconipoveda wrote:Hi, I have a 7200 for Demo. 1 enclosure 8 disks x 450Gb. 4 disk x cage.

Created a R1 CPG and then tried to create a FPVV of 100Gb but the system says I don't have enought space. Then I created a 1Tb TPVV without problem. Any idea of what I'm missing or missunderstanding about 3PAR's space management.

Thanks for your help.

===========
3PAR Thin provisioning allows you to over provision your storage.
As far a the space to the VV goes , it re-collects from the CPG.

So in above if you start writing data, the CPG would ask for space for the VV associated, and will notify you of space warning ..
Hope I am correct..