exFAT

[Bjørn Rørslett]

This must be a misunderstanding as to how RAID 5 or other schemes work.

With N disks each of size M or larger, the storage capacity is (N-1)*M for a RAID 5 layout. The parity information is distributed all over the members of the disk set.  For example, with 4 (N) disks each of size 4 TiB (M), you get an RAID 5 volume of 12 TiB.

The least "efficient" RAID scheme is RAID 1/10, which in the example above would provide N*M/2 or an 8 TiB volume. RAID 6 results in (N-2)*M thus in this example also 8 TiB. There are numerous other RAID schemes but these are hardly practical for the comparatively small disk arrays of the home user.

The storage used for the operating system of the NAS is very small so can be safely ignored in these calculations.

[Ron Scubadiver]

I read somewhere exFAT is not as robust as other file systems because there is only one copy of essential system areas. 

[Bjørn Rørslett]

Journaled file systems are more robust, true enough. exFAT in the normal implementation lacks this feature. It does have checksum as integral parts of the file system, and there is a transaction-adopted version (TexFAT) as well.

An NAS uses journaled file systems thus are not vulnerable in the same sense as a USB stick or SD card. Communication over the network to the computers accessing the NAS is through SMB/CIFS or other universal protocols.

[Shane]

Hi Charlie
I also use PC desktop and Mac laptop. My external image drive is formatted NTFS and I use Paragon NTFS driver for W7/Mac read/write compatibility.
I also have a 240GB Sandisk 500 USB with two partitions (partitioned with iPartion which supports HFS and NTFS), one NTFS for image files and LR library, and the other smaller partition for HFS as a swap drive for CS when I hook it up to the Mac. So far works quite nicely for this application and swapping LR library back and forth between PC and Mac.