RN104

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wrote:

Have two times 1tb in plus a 4tb 3 drives in total 6tb in total nothing on them just put the 4tb in new gone through its set up but is only giving me available space of 1.8 tb surely this isnt correct?

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The capacity rule for single-redundancy XRAID (protection from 1 drive failure) is "sum the drives and subtract the largest).  That is optimal, there is no way to do better.

 

That rule works out to 2 TB in your configuration (6 TB - 4TB) - and the NAS displays in TiB.  2 TB is the same as 1.83 TiB.

 

Your particular drive configuration isn't very good for RAID - it simply can't use most of the space on your 4 TB drive, and still provide access to your files if the 4 TB drive fails.

 

One option is to get an additional 4 TB drive.  That would increase your volume to 6 TB (5.45 TiB).

 

You could also set it up again with just the 2x1TB drives installed.  That will give you a 1 TB RAID-1 volume with protection for failure.  Then change to flexraid, and create a second unprotected volume using jbod.  That will give you a 4 TB volume (5 TB total).  You'd put your most critical files on the 1 TB volume.

 

One possibility I don't recommend is to set it up again using RAID-0 as a single 6 TB volume.  That does give you the most space.  But if any single disk fails, all your data is lost.

 

Note that while RAID is a good thing, you still do need backups to keep your data safe.