3 Node Simplivity cluster usable capacity

[steez]

Hello everyone,

I have a question about Simplivity usable space in 3 node clusters.

As I understand if in 2 node cluster reported physical space is 59TB, that means the actual usable space is ~29TB (50% goes HA), similar to RAID1

In 3 node case, does RAID5 level of usable space and availability apply? Meaning only 1 node can fail and usable space would 2/3 of total physical space and 1/3 to HA?

[MikeSeden]

Here is the general formula I found to use when sizing for the SimpliVity DVP capacity efficiency:

( Production data + (production data * percent expected growth/100) ) / 2.25 efficiency

For example a customer with 125 TB of data and expected growth of 25%:

( 125 + ( 125 * 25/100 ) ) / 2.25 = ~69.44 TB

If a node failed, I would remove that amount of capacity from the equation-
Here is a good web page that may help you with usable capacity.
http://www.vhersey.com/2016/05/16/simplivity-effective-storage-capacity/

[Mahesh202 · Accepted solution]

Hi Steez

Hope you are doing well.

We always keep two full copies of hives that is why It will be a total capacity / 2
OR 
Usable capacity per cluster =[ #nodes * (Usable capacity per node)] /2

Hope this helps.!!

Regards
Mahesh.