ReadyNAS NV+ v2 with 4 4TB drives in raid5 showing 10TB volume

[wicked1980]

I got 4 new 4TB harddrives (wd green).

Did a factory reset with the new drives installed and used RAIDar to configure them in RAID5.

One volume is automatically created with a capacity of 10TB. Not the expected 12 TB

Do I have to expand the volume after the Sync proces is complete (Disk 4 is syncing)?

[StephenB]

The NAS will report the volume size in TiB (1024*1024*1024*1024 bytes) not TB (1000*1000*1000*1000).

So you should be seeing  about 10.9 TB on the dashboard. 12*(1000/1024)*(1000/1024)*(1000/1024)*(1000/1024) = 10.91.

[wicked1980]

Correct. But that does not account for the missing 2 tb (give or take)

4 x 4 tb in RAID5 = 12288 gb due to parity

[mdgm-ntgr]

10.91TB rounded down is 10TB.

StephenB already explained that like most computers we use a different measurement to disk manufacturers.

It's a bit like whether you measure distance in kilometres or miles. You may get a different number for the distance from A to B, but the distance is still the same.

Whether you use base 10 or base 2 for measuring space on a data volume makes a significant difference to the number you get.

Using TB (uses base 10) you would get (4-1)*4 = 12TB = 12288GB.

12*(1000)^4/1024^4=10.91. 12TB=10.91TiB. It's still the same amount of space, just a different way of measuring it. Like most computers we use TiB (uses base 2) but call it TB. This can get a bit confusing as disk manufacturers use TB (base 10), but it's the way it's always been as far as I can remember.

[wicked1980]

Ah, I get it now. Misread/Misinterpreted StephenB's post.

Thank you