Hi Didi7

Could you give a little more context, please? Where did you see this? Is the cluster RF2? What are the features that the cluster is using (erasure coding, for example)? You can project the usable space using Nutanix Sizer.

Hi Alona,

we use RF2 in all our Nutanix clusters. I can see those figures by clicking Home => Hardware => Table => Disk (Prism Element) …

There I can see, that 531.82 GiB are useable from a 960GB SSD, same in another cluster, where we have 1.92 TB SSDs (instead of 960GB) and there the usable size is 1.22TB.

Now I would like to know how much space is available from a 3.84TB SSD, the percentage of ususable space from different SSDs differ a lot.

Hi Didi7,

Usable space for SSDs will vary depending on whether CVM is installed on the disk, if it’s an all-flash cluster or a hybrid and many other variables. Roughly you can expect to see 50%. In real life after conversion from TB/GB to TiB/GiB, oplog calculations and the rest the usable space is a bit higher than 50%. 

Drive Breakdown explains some of what affects the usable capacity.