We see the data size for an individual share from the "Consumed" column in "Shares", but there is no "per share" indication of the snapshot size for it.
(Case #27372419)
Any chance that the per share size of snaphots are getting supported?
That would allow you to see how much data is exclusive to an individual snapshot but wouldn't tell you how much data is consumed by snapshots for the share (most data that is not in the current data would be in more than one snapshot)
Would I not get the right result if I add the size of all snapshots for that share?
No, you wouldn't. The "size" of a snapshot turns out to be a rather slippery - and meaningless - concept..You can talk about how much disk space the main share uses, and how much disk space the entire subvolume uses (share + all snapshots). But you can't really talk about how much space an individual snapshot uses.
Here is a simple example. Imagine I have a main share with 10 files in it, each are 100 MB long. Total space if the subvolume is 1000 MB, total space of the main share is also 1000MB.
I create snapshot X. At this point, the total subvolume and the main share are still is 1000 MB. All the blocks are held in common, so you can think of it as "The snapshot X uses no space".
Now I delete file A in the main share. The subvolume remains 1000 MB, but the main share is only 900 MB. You can still think of this as "the snapshot size is 100 MB".
Now I create snaphot Y. All the blocks in snapshot Y are in the main share, so you can still think of this as snaphot X uses 100 MB and snapshot Y uses no space.
Now I delete file B, and the concept of snapshot sizefalls apart. The subvolume remains 1000 MB, the main share size becomes 800 MB. The total space in both snapshots X and Y is 200 MB. But you can't meaningfully say how much disk space each snapshot uses because the data blocks in File B are shared by both snapshots..
ok, so the only option is to have a volume for each share
It is possible to show the space taken by the combined snapshots in the share, if you assume that no one (including apps) has used --reflink across subvolumes.
My guess is that Netgear is hesitant to make that assumption - there would certainly be a lot of confusion when the assumption is wrong.
Do you know if: ->Can I enable quota without any risk?
You can enable it, but you should do that via the web ui. Click on the settings wheel on the volume page, and then choose "settings" - you'll see if there.
I have quota enabled on my two RN52x ReadyNAS, and haven't had any problems. If you have an ARM-based NAS (particularly an RN100 series) it might impact performance and memory use. With OS 6.7.4, an OS-reinstall should turn off the quota setting, so it can be reversed without data loss even if you were to lose network access.
