EcrosTechWiki | NetworkStorage / The System Volume

First, a Rant About QNAP's Documentation

The system volume has a couple of brief mentions in the QTS 5.0.x User Guide (Version 7, 08/12/2022). If you click the 'More' icon in the task bar, select 'About' and hunt around in the resulting pop-up, you will find the System volume name, written like this - Storage - SYSTEM(more). There is mention of limitations if you use the obscure Virtual JBOD feature. I quote below the entire section in the User Guide on the system volume, which is on page 220 of 535 and has no entry on the contents pages. Note also that you are so inundated by 'wizards' as you try to set up your NAS that you get the impression you're not supposed to read the User Guide, an impression reinforced should you actually try to do that.

The system volume is a regular static or thick volume that QTS uses to store system data such as logs, metadata, and thumbnails. By default, applications are installed to the system volume. If no system volume exists, either because the NAS has recently been initialized or the system volume was deleted, QTS will assign the next static or thick volume that you create as the system volume.

Important
QNAP recommends creating a system volume of at least 10 GB. This is to prevent errors caused by insufficient system volume space

So, it turns out that after creating your storage pool, you should really, really create a system volume and you should do this before you create any user volumes. I knew nothing of this and proceeded to create a 'thick' volume of 400 MB which I intended to share on the network. Checking my work, I found a folder called 'Public' that I hadn't created, an App, 'Malware Remover', using 19.73 MB, that I hadn't installed and 16.14 GB of missing storage space that I couldn't explain. I can't now remember how I figured out what was going on, but I removed that volume and began again.

Creating the System Volume

In my otherwise empty storage pool, I began by creating a thick volume named 'SYSTEM'. I specified a size of 20 GB and gave it an alert threshold of 80%. After formatting, QTS spent some time 'Creating Default Folders'. After it was done, there only seemed to be one folder, 'Public', which contained sub-folders @Recycle and @Recently-Snapshot. Several days later, after more progress, I found the Hybrid Backup Sync App installed here, with a size of 163.86 MB but taking up 290.84 MB.

For more information about things like 'thick' volumes and 'alert thresholds', please wait until the next page, User Volumes. Here I want to talk specifically about the system volume.

I can't recall why I chose the name (alias?) 'SYSTEM', but I seem to remember being confident about it, so I don't think I just plucked it out of thin air. It probably doesn't matter, but I'm going to leave it the way it is.

I do recall where the 20 GB size came from. QNAP recommends at least 10 GB (see rant above). But when I mistakenly created what I intended to be an ordinary user volume of 400 GB, I found that 16.14 GB was missing. Having no idea where this went, I became worried that QTS somehow squirreled it away in the expectation of needing it 'to store system data'. I do not want to deal with 'errors caused by insufficient system volume space' in a couple of years time, so I'm starting out with twice what QNAP recommend and 24% more than the missing space. As I write this, I realize that I should add that the system volume can be resized, just like any other, so I might have overreacted. On the other hand, I'm only able to resize it to 21 MB or above, so QTS definitely does not want it to be any smaller. I'll stick with my choice, but if you're following along you might try a larger system volume.