How to Check NAS Drive Health with S.M.A.R.T. Tests

Running S.M.A.R.T. tests on your NAS drives is the single most effective thing you can do to catch failing drives before they take your data with them. Every modern NAS. Whether it's a Synology DS925+, a QNAP TS-464, or an Asustor AS5404T. Includes built-in tools to run S.M.A.R.T. diagnostics on installed drives. The tests take minutes to configure, can be scheduled automatically, and give you early warning of drives that are heading toward failure. This guide walks through exactly how to do it on the major NAS platforms available in Australia, what the output means, and how to interpret the results without a degree in storage engineering.

What Is S.M.A.R.T. and Why Does It Matter for NAS?

S.M.A.R.T. stands for Self-Monitoring, Analysis, and Reporting Technology. It is a firmware-level monitoring system built into almost every hard drive and SSD sold in the last two decades. The drive itself continuously tracks dozens of internal health metrics. Things like read error rates, spin-up time, reallocated sector counts, uncorrectable error counts, and temperature. And exposes those values to the operating system on request.

In a NAS context, this matters enormously. A NAS is typically running 24/7, often storing data you cannot easily recreate, and the drives inside are under sustained read/write load that desktop drives were never designed for. NAS-grade drives like Seagate IronWolf and WD Red Plus include enhanced S.M.A.R.T. attributes specific to NAS workloads. But even consumer drives report the core attributes that give you early warning of impending failure.

The critical thing to understand: S.M.A.R.T. does not predict all failures. Sudden mechanical failures. A head crash, a spindle motor seizing. Can happen with zero S.M.A.R.T. warning. What S.M.A.R.T. does catch reliably is gradual degradation: growing bad sector counts, increasing error rates, and temperature excursions. These are the most common failure modes, and they almost always show up in S.M.A.R.T. data days or weeks before the drive stops responding.

The Two Types of S.M.A.R.T. Tests

Every NAS platform offers at least two test types. Understanding the difference helps you schedule them appropriately:

• Quick Test (Short Test): Runs in under two minutes. Tests the drive's electrical components, servo, and read/write functionality at a high level. Good for a rapid health check. Run this any time you suspect a problem or after a NAS reboot. Does not scan the full disk surface.
• Extended Test (Long Test): Performs a complete surface scan of every sector on the drive. On a 4TB drive, this typically takes 3-6 hours depending on drive speed and condition. A degraded drive will take longer. This is the definitive health check. It will find bad sectors that the Quick Test misses entirely. Run this monthly on drives that are more than two years old, and quarterly on newer drives.

Some platforms also expose a Conveyance Test, which is designed to detect damage that may have occurred during shipping or handling. If you have just installed new drives into a NAS, run a Conveyance Test before you load any data onto them.

How to Run S.M.A.R.T. Tests on a Synology NAS

Synology's DSM (DiskStation Manager) has some of the most polished S.M.A.R.T. tooling of any NAS platform. The relevant section lives inside Storage Manager.

1. Log into DSM and open Storage Manager from the main menu.
2. In the left sidebar, click HDD/SSD. You will see all installed drives listed with their current health status.
3. Select the drive you want to test and click Health Info. This opens the full S.M.A.R.T. attribute table for that drive.
4. To run a test manually, click the S.M.A.R.T. Test tab, then select either Quick Test or Extended Test and click Start.
5. To schedule automatic tests, go to Storage Manager → HDD/SSD → Settings → S.M.A.R.T. Test Scheduler. Set a monthly Extended Test during low-traffic hours. Early Sunday morning is a common choice.

Synology will send an email alert (configured under Control Panel → Notification) if a drive's S.M.A.R.T. status changes to Caution or Critical. Set this up the moment your NAS is configured. It is one of the most important notifications in DSM. Synology NAS units like the DS925+ (from $995 at Mwave and Scorptec) include this functionality out of the box with no additional licensing required.

How to Run S.M.A.R.T. Tests on a QNAP NAS

QNAP's QTS operating system handles S.M.A.R.T. testing through the Storage & Snapshots application. The interface is more complex than Synology's but exposes more detail.

1. Open Storage & Snapshots from the QTS desktop or App Center.
2. Click Storage in the top navigation, then select Disks/VJBOD from the left panel.
3. Click on the drive you want to test. A panel opens on the right showing drive information.
4. Click the Actions dropdown and select SMART Test.
5. Choose Quick Test, Extended Test, or Conveyance Test and click OK.
6. To view S.M.A.R.T. attributes, select the drive and choose SMART Info from the Actions menu.

To schedule automatic S.M.A.R.T. tests on QNAP, navigate to Storage & Snapshots → Storage → Global Settings → SMART. From here you can configure scheduled Quick and Extended tests independently and set the notification threshold. QNAP also integrates S.M.A.R.T. alerts with its notification system under Control Panel → Notification Center. Configure email or SMS alerts here so you are notified immediately if a drive status changes.

QNAP models currently available in Australia range from the entry-level TS-433 (from $639 at PLE Computers and Scorptec) up to enterprise units like the TS-464 (from $989 at PLE Computers and Scorptec). S.M.A.R.T. functionality is consistent across the range regardless of model tier.

How to Run S.M.A.R.T. Tests on an Asustor NAS

Asustor's ADM (Asustor Data Master) operating system places S.M.A.R.T. tools inside the Storage Manager application, similar to Synology's layout.

1. Log into ADM and open Storage Manager.
2. Click Disk in the left sidebar. All installed drives are listed here.
3. Select a drive and click the S.M.A.R.T. tab in the drive detail pane.
4. Click Quick Test or Extended Test to run a manual scan.
5. The full S.M.A.R.T. attribute table is displayed in the lower portion of the screen, including all raw values and threshold comparisons.

Asustor's scheduling is found under Storage Manager → Disk → S.M.A.R.T. → Scheduled Test. You can set separate schedules for Quick and Extended tests. Email notification for S.M.A.R.T. status changes is configured under Settings → Notifications.

Asustor NAS units are distributed in Australia exclusively through Dicker Data as of 2026. Models like the AS5404T (from $879 at Mwave) and the AS6704T (from $1,013 at Mwave) both include full S.M.A.R.T. testing through ADM with no additional apps required.

Reading S.M.A.R.T. Results: What the Attributes Mean

The raw S.M.A.R.T. attribute table can look intimidating. Dozens of rows of numbers with names like "Raw Read Error Rate" and "Spin Retry Count." Most of it can be ignored. These are the attributes that actually matter:

Attribute	ID	What It Means	When to Worry
Reallocated Sector Count	05	Sectors the drive has marked as bad and remapped to spare areas	Any non-zero value warrants monitoring. A value above 5 and climbing = replace soon.
Uncorrectable Sector Count	C6 / BB	Sectors that could not be read or corrected	Any non-zero value is serious. Treat this as a replacement trigger.
Current Pending Sector Count	C5	Sectors flagged as unstable, waiting for reallocation	Any non-zero value is a red flag. If this persists after a surface scan, replace the drive.
Spin Retry Count	0A	Times the drive had to retry to reach operating speed	Non-zero values suggest spindle motor issues. Watch for increases over time.
Reallocated Event Count	C4	Number of reallocation events (not just sectors, but events)	Rising values alongside ID 05 confirm active degradation.
Power-On Hours	09	Total hours the drive has been powered on	Context only. NAS-grade drives are rated for 8,760 hours/year. A 4-year-old drive has ~35,000 hours.
Temperature Celsius	BE / C2	Current drive temperature	Keep HDDs below 45°C. Sustained operation above 50°C accelerates wear.

The overall S.M.A.R.T. status shown by your NAS (Good, Caution, Bad) is a summary derived from these attributes. A drive can show "Good" overall while individual attributes are beginning to degrade. This is why checking the raw attribute table matters, not just the headline status. Pay particular attention to Reallocated Sector Count (ID 05) and Current Pending Sector Count (ID C5). A drive with either of these climbing over successive tests is telling you it is failing, regardless of what the summary status says.

How Often Should You Run S.M.A.R.T. Tests?

The following schedule suits most home and small business NAS deployments:

• Quick Test: Weekly. Schedule overnight on a low-traffic day. Takes under two minutes and adds negligible load to the drives.
• Extended Test: Monthly for drives over two years old. Quarterly for newer drives. Schedule during a maintenance window. A full surface scan on a 4TB drive takes 3-6 hours and generates significant read load. Do not run Extended Tests during business hours if your NAS is serving active workloads.
• Immediate manual test: Any time you hear unusual sounds from the NAS, after a power outage, or after the NAS reports any storage-related warning. Run a Quick Test first, then an Extended Test if anything looks abnormal.

Most NAS platforms will also run background scrubbing tasks (called "Data Scrubbing" on Synology, "Storage Pool Scrubbing" on QNAP) that serve a complementary purpose to S.M.A.R.T. tests. They verify data integrity across the RAID, not just individual drive health. Both are worth running regularly and they work together, not as substitutes for each other.

What to Do When S.M.A.R.T. Reports a Problem

A S.M.A.R.T. warning does not mean your data is gone. It means your window to act is open and closing. The priority order is:

1. Verify your backup immediately. Before you do anything else, confirm that your most recent backup is complete and restorable. If you are running a NAS without an offsite backup, this is the moment that assumption becomes a crisis.
2. Do not power cycle the drive unnecessarily. A drive with bad sectors may be readable now but fail to spin up cleanly after a power cycle. If the data on the drive is critical and has no backup, consider leaving the NAS running while you copy the data off.
3. Order a replacement drive before the failing drive is completely dead. Do not wait for a full failure. In 2026, NAS-grade drive prices have risen significantly. 4TB NAS drives that were under $160 in early 2025 are now consistently above $200. Order the replacement while the failing drive is still functional.
4. If running RAID, let the rebuild complete before handling anything else. After replacing the failed drive, the RAID rebuild will begin automatically. Do not interrupt it. Keep the NAS on a UPS during the rebuild if possible. A power interruption during a RAID rebuild on a degraded array can cause data loss even on RAID 5 and RAID 6.
5. Run an Extended Test on the new drive after installation and before the RAID rebuild. A conveyance test first, then an Extended Test, confirms the replacement drive is not DOA before you depend on it.

S.M.A.R.T. Testing via Command Line (Advanced Users)

Most NAS platforms are Linux-based and include the smartmontools package, which means you can run S.M.A.R.T. tests directly from an SSH terminal with more control than the GUI allows. This is useful for scripting, for accessing attributes that the GUI does not display, or for running tests on a headless NAS where the web interface is unavailable.

Enable SSH access on your NAS (usually under Control Panel → Terminal & SNMP on Synology, or Control Panel → Network & File Services → Telnet/SSH on QNAP) before attempting this. Always disable SSH again after use unless you have a specific reason to leave it open.

Common smartctl commands:

• View S.M.A.R.T. attributes: smartctl -a /dev/sda (replace sda with the relevant device node)
• Run a Quick Test: smartctl -t short /dev/sda
• Run an Extended Test: smartctl -t long /dev/sda
• Check test progress: smartctl -l selftest /dev/sda
• List all drives: ls /dev/sd* or smartctl --scan

The output from smartctl -a includes every S.M.A.R.T. attribute, the self-test log (showing results of previous tests), and the error log (showing any errors the drive has logged internally). This is significantly more information than the GUI displays and is worth reviewing on any drive you are monitoring closely.

Temperature Management: The S.M.A.R.T. Attribute You Ignore at Your Peril

Drive temperature is consistently underestimated as a factor in NAS drive longevity. S.M.A.R.T. reports current temperature, and some platforms (including Synology DSM) will send alerts when a drive exceeds a configured threshold. The practical guidelines for NAS drives:

• Ideal operating range: 30-40°C for HDDs. Below 25°C is also suboptimal. Very cold drives have higher error rates during spin-up.
• Acceptable maximum: 45°C sustained. Above this, error rates increase measurably and drive life shortens.
• Danger zone: Above 50°C. If your NAS is consistently running drives above 50°C, add active cooling, improve airflow, or reduce drive density. Cramming eight drives into a chassis with inadequate airflow is a common cause of premature failure in home NAS setups.

In an Australian context, summer ambient temperatures in uninsulated home offices or server rooms can push drive temperatures well above safe limits. If your NAS is in a poorly ventilated cabinet in a Sydney or Brisbane summer, monitor temperature closely. A $30 USB fan pointed at the NAS air intake can meaningfully reduce drive temperatures in marginal environments.

Buying Replacement Drives in Australia: What to Know

When S.M.A.R.T. tells you a drive needs replacing, you need to source a replacement quickly. A few practical notes for Australian buyers in 2026:

NAS-grade drive prices have risen sharply from early 2025 levels. Distributors are securing stock allocations further forward than usual. A sign of how constrained the global HDD supply chain has become. When shopping for a replacement, check Mwave, PLE Computers, and Scorptec. Pricing is generally uniform across retailers. Most Australian NAS resellers operate on 3-5% margin, which leaves very little room for price variation. The meaningful difference between retailers is stock availability and what happens when something goes wrong, not the price.

Always buy NAS-rated drives (Seagate IronWolf, WD Red Plus, or equivalent) rather than desktop drives for a NAS replacement. Desktop drives are not rated for the vibration, sustained load, and always-on duty cycles of a NAS environment. Using a desktop drive as a NAS replacement is a short-term cost saving that tends to create another S.M.A.R.T. problem within 12-18 months.

Australian Consumer Law applies when you purchase drives from Australian retailers. If a replacement drive fails within a reasonable timeframe, you have rights to a remedy. Keep your proof of purchase. Grey market drives purchased from international sellers may be cheaper but come without guaranteed ACL protection.

Setting Up S.M.A.R.T. Email Alerts: Don't Skip This Step

Running S.M.A.R.T. tests manually is useful. Getting an email the moment a drive's status changes is essential. Every major NAS platform supports email notifications for S.M.A.R.T. events. And it takes less than five minutes to configure.

On Synology DSM: Control Panel → Notification → Email. Configure an SMTP server (Gmail, Outlook, or your own mail server) and enable alerts for storage-related events. DSM will automatically notify you of S.M.A.R.T. status changes, drive removal, RAID degradation, and scheduled test failures.

On QNAP QTS: Control Panel → Notification Center → Service Account and Device Pairing. QNAP supports email, SMS, and push notifications through its myQNAPcloud service. For S.M.A.R.T.-specific alerts, ensure "Hardware" and "Storage" notification categories are enabled.

On Asustor ADM: Settings → Notifications. Configure email through SMTP and enable disk health notifications. ADM will send alerts for S.M.A.R.T. status changes and test failures.

If your NAS is accessible remotely. Whether via Synology QuickConnect, QNAP myQNAPcloud, or Asustor EZ-Connect. These notifications will reach you regardless of where you are. Be aware that on some NBN connections, particularly those on CGNAT (common with some NBN resellers), direct remote access to your NAS may not be possible without using the vendor's relay service or configuring a VPN. This does not affect email notifications, which are outbound from the NAS, but does affect whether you can log in remotely to investigate if an alert fires.

Related reading: our NAS buyer's guide.

Related reading: our NAS hard drive guide.

Use our free Drive Failure Risk Calculator to understand your real data loss risk.

How long does a S.M.A.R.T. Extended Test take on a NAS drive?

A typical Extended Test on a 4TB NAS hard drive takes between 3 and 6 hours. Larger drives take proportionally longer. An 8TB drive may take 6-12 hours. A drive that is already degraded will take longer than a healthy one, because it has to retry reads on bad sectors. If an Extended Test is taking significantly longer than expected, that is itself a sign of drive health problems. Schedule Extended Tests during off-hours to avoid impacting NAS performance.

Will running S.M.A.R.T. tests affect NAS performance or risk damaging my drives?

Quick Tests are very low impact and can be run at any time with minimal effect on NAS performance. Extended Tests perform a full surface scan and generate sustained read load. You may notice slower NAS response during an Extended Test if your NAS is also serving active file transfers or running VMs. S.M.A.R.T. tests do not damage drives. The read operations involved are no different from normal data access. However, it is worth noting that running an Extended Test on a severely degraded drive may, in rare cases, surface a pending failure. This is a reason to run tests earlier rather than later. Not a reason to avoid them.

A S.M.A.R.T. test says my drive is 'Good' but it makes clicking noises. Should I trust it?

No. S.M.A.R.T. does not catch all failure modes. Clicking noises (sometimes called the "click of death") indicate a mechanical problem. Typically a read/write head that is failing to park or seek correctly. A drive can produce these sounds before the failure registers in S.M.A.R.T. attributes. If your drive is clicking, treat it as a failing drive regardless of S.M.A.R.T. status. Back up the data immediately and order a replacement. Do not rely on a "Good" S.M.A.R.T. status to override what you can hear.

Can I run S.M.A.R.T. tests on SSDs in my NAS?

Yes. Most modern SSDs support S.M.A.R.T. and expose health attributes through the same interface as HDDs. However, the relevant attributes differ. For SSDs, the key metrics to watch are Wear Leveling Count (how much of the flash memory's write endurance has been consumed), Uncorrectable ECC Error Count, and the vendor-specific Percentage Used or Remaining Life attributes. Most NAS platforms will display these correctly for SATA SSDs. NVMe SSDs in NAS cache slots may require checking through a separate interface depending on the platform. Asustor, QNAP, and Synology all support S.M.A.R.T. monitoring for SATA SSDs installed as data drives.

How many reallocated sectors are too many? When should I replace a drive?

Any non-zero Reallocated Sector Count (S.M.A.R.T. ID 05) warrants monitoring. A single reallocated sector on a new drive is worth noting. A count above 5 that is growing over successive tests is a strong replacement signal. If the Current Pending Sector Count (ID C5) or Uncorrectable Sector Count (ID C6/BB) is non-zero, treat the drive as a replacement priority regardless of the total reallocated count. The direction of travel matters as much as the absolute number. A stable count of 3 reallocated sectors on a five-year-old drive is less concerning than a count that has jumped from 0 to 8 in the last month.

Do I still need S.M.A.R.T. tests if my NAS is running RAID?

Yes, absolutely. RAID protects your data from a drive failure after it has occurred. S.M.A.R.T. tests help you catch degrading drives before they fail completely, giving you time to replace them on your schedule rather than in an emergency. RAID 5 in particular is vulnerable during a rebuild: if a second drive fails while a rebuild is in progress, all data in the array is lost. Proactive S.M.A.R.T. monitoring reduces the chance of arriving at that scenario. Think of RAID as your safety net and S.M.A.R.T. as the early warning system that tells you when the net is about to tear.

Can I check NAS drive health remotely if I'm not at home?

Yes, if your NAS is accessible remotely. Synology QuickConnect, QNAP myQNAPcloud, and Asustor EZ-Connect all allow access to the NAS management interface from any internet connection. From there you can view S.M.A.R.T. status and run tests exactly as you would locally. One caveat for Australian users: some NBN connections use CGNAT (Carrier-Grade NAT), which prevents direct inbound connections to your NAS. This does not affect vendor relay services like QuickConnect or myQNAPcloud, which work through outbound connections from the NAS. If you are using a self-hosted VPN for remote access, CGNAT will block it. Contact your NBN provider to request a public IP, which most providers offer at no additional charge or for a small monthly fee.