Storage

Every volume, every drive

Q: What temperature is too hot for a NAS drive?

The app colours a drive amber past 45 degrees C and red past 55 degrees C, and the system temperature amber past 50 and red past 60. Those thresholds also feed the health badge on the home screen, so a hot drive shows up there without you going looking.

Three sub-views: Volumes & Pools for capacity and RAID, Disk Health for SMART and temperature per drive, and External for anything plugged into the back.

Storage volumes and drives in Syno Manager

On this page

Volumes & Pools
The drive list
Disk Health & SMART
Temperature thresholds
External & safe eject
What it will not do

Volumes & Pools

Capacity, at a glance

Each volume gets a card with its name, its RAID type, its status and how many drives back it, over a usage bar with used, percentage, total and free.

Shown	Meaning
Volume name	As DSM names it - `VOLUME_1`, and so on.
RAID type	RAID 5, SHR, RAID 1, Basic - whatever the pool underneath actually is.
Status	The volume's own state: normal, degraded, crashed. A degraded array is the one thing on this screen worth acting on today.
Drive count	How many physical drives the volume spans.
Usage bar	Green normally, amber past 80% and red past 90%. Those are the same thresholds the health badge uses.
Used / Total / Free	All three, because "70% full" and "13 TB free" answer different questions.

Drives

What is in each bay

Below the volumes, every physical drive by bay number.

Bay - Disk 1, Disk 2, and so on, matching the labels on the chassis.
Model - the drive's own model string.
Vendor and type - the manufacturer and whether it is an HDD or an SSD. A drive whose vendor the NAS could not identify is shown as Unknown rather than being guessed at.
Temperature, coloured against the thresholds below.
SMART verdict - SMART OK when the drive's own self-assessment is healthy.

Disk Health

SMART, and a test you can start

The Disk Health sub-view is the same drives with more room: capacity, type, temperature and SMART state each get their own chip, and every drive carries a Quick SMART Test button.

Quick SMART Test asks the drive to run its own short self-assessment. It takes a couple of minutes and does not interrupt anything using the volume.
The verdict is the drive's, not ours. SMART is the drive reporting on itself; the app relays it. A drive that says it is fine and then fails is a limitation of SMART, not of the reading.
An unreadable SMART state is shown as unknown, never as healthy. A missing reading and a good reading are different things and are never merged.

Disk Health showing every drive with SMART status, temperature and a Quick SMART Test button

The numbers behind the colours

Thresholds

Nothing here is a guess about your hardware - these are the points at which the app changes a colour and, where relevant, the home screen's health badge.

Reading	Amber at	Red at
Drive temperature	45°C	55°C
System temperature	50°C	60°C
Volume usage	80%	90%
UPS charge	below 50%	below 20%

Switch between °C and °F in Settings › Temperature Unit. Every temperature in the app follows it immediately, including the ones on the home screen and in the widgets.

External

USB, eSATA and safe eject

Two sections: External Storage for drives you can mount and eject, and USB Devices for everything else plugged in - a UPS, a printer, a dongle.

Eject is confirmed by the drive leaving. The app does not report success because the request came back OK; it re-reads the device list and only says the drive is ejected once it is genuinely gone. That is the difference between "safe to unplug" and "probably safe to unplug".
A busy drive cannot be ejected. One that is formatting or initialising is refused, with the reason, rather than being yanked mid-write.
Nothing attached says so plainly. An empty list reads "No external drives attached" - not an empty box you have to interpret.

Boundaries

What this screen will not do

Storage is the one place where a mistaken tap is not recoverable, so the app reads far more than it writes.

It will not create, expand or delete a volume or pool. Those live in DSM's Storage Manager, on a screen big enough to show what you are about to do.
It will not repair a degraded array. It will tell you, clearly and on the home screen, that one is degraded.
It will not format anything.
It will not run a full SMART test - only the quick one. A full surface scan takes hours and belongs somewhere you are not going to walk away from.

Scrubbing, rebuilds and parity checks show up as running operations while they are in progress, so you can watch one finish from the app even though you started it in DSM.

Common questions

Storage FAQ

Can I see SMART status for each drive?

Yes. The Disk Health sub-view lists every drive with its model, whether it is an HDD or SSD, its capacity, its temperature and its SMART verdict. You can also start a Quick SMART Test on any drive from the phone.

What temperature is too hot for a NAS drive?

The app colours a drive amber past 45°C and red past 55°C, and the system temperature amber past 50°C and red past 60°C. Those thresholds also feed the health badge on the home screen.

Can I safely eject a USB drive from the app?

Yes, from the External sub-view. The eject is confirmed by the drive actually leaving the device list, not by the request being accepted. A drive that is formatting or initialising cannot be ejected.

Can I create or expand a volume from the app?

No. Creating, expanding and repairing volumes and pools are done in DSM's Storage Manager. The app reports what your storage is doing and lets you act on drives; it does not restructure your array from a phone.

Why does a drive say Unknown for its vendor?

Because the NAS did not report one. The app shows what it was told rather than inferring a manufacturer from the model string, which would be a guess presented as a fact.