What does hard drive long DST check mean?

Hard drive long DST check refers to an extended diagnostics test that is run on a hard disk drive. DST stands for “Drive Self Test” and it is a feature built into most hard drives that allows them to perform self-checks and diagnostics.

A long DST check is more thorough and comprehensive than a standard quick DST check. It scans the entire hard drive surface, checking for bad sectors, integrity of the physical disk structures, and other problems. This long test can take several hours to complete, depending on the size of the hard drive.

Some of the key things to know about hard drive long DST checks:

Purpose of a Long DST Check

– To detect any latent sector errors that may not show up in a quick check
– Identify potential hardware problems or deterioration that may impact drive health
– Confirm the drive is functioning properly before relying on it for important data

When Is a Long DST Recommended?

– When a hard drive is new and being initialized
– After a hard drive has encountered read/write errors or bad sectors
– Periodically as part of a hard drive health check/maintenance
– Before entrusting a drive with critical data

How Long Does It Take?

– Hours, depending on hard drive capacity
– Generally much longer than a quick DST test
– 500GB HDD – Approximately 2 hours
– 1TB HDD – Approximately 3 hours
– 2TB HDD – Approximately 5 hours
– 4TB HDD – Approximately 9 hours

Now let’s dig into the details on hard drive DST checks and how you can use them to diagnose and monitor hard drive health.

What Is a Hard Drive Self-Test (DST)?

A hard disk drive self-test, also known as Drive Self Test (DST), is an internal diagnostics program built into the firmware of most hard drives. It allows the drive to perform a self-check autonomously by running various tests on the mechanical components, read/write heads, and data storage platters.

The DST checks for a variety of potential issues:

Read/Write Head Alignment

DST verifies that the precise alignment needed for the read/write heads to function is within acceptable tolerances. Being out of alignment can cause errors.

Electrical Signals

The electronics that control the heads and platters are checked for correct voltages and signal strength.

Spin Speed

The spindle rotation speed is checked to ensure the platters are spinning at the prescribed RPM. Too slow or fast will cause read/write problems.

Bad Sectors

DST does a full scan of the drive surface and maps out any bad sectors that are not properly retaining magnetic encoding of data.

Mechanical Components

The motors, bearings, armatures and other mechanical parts are checked for problems like excessive vibration or noise.

By running these tests internally, the DST helps identify early signs of component degradation or damage before catastrophic hard drive failure occurs.

Quick DST vs Long DST

Hard drives support both quick and long duration DST checks:

Quick DST

– Takes 2 minutes or less
– Checks electronic components
– Identifies any fatal flaws that make drive inoperable

Long DST

– Takes several hours
– Does full scan of entire platter surface
– Maps out all questionable and bad sectors
– Very comprehensive test of overall drive health

The quick DST is suitable for basic functionality testing. The long DST provides a much more rigorous check and is recommended for examining drives that will be used for important data storage.

It is also advised to periodically run long DST tests as part of a storage maintenance routine to identify any deteriorating conditions early.

When Should You Run a Long DST Check?

Here are some situations where performing a long hard drive self-test is recommended:

New Hard Drive Installation

Before you start using a new hard drive, a long DST provides assurance that it is functioning normally without any factory defects. Catching problems early allows for a simpler replacement.

Suspicious Drive Behavior

If you notice unusual noises, slow performance, or errors coming from a hard drive, the long DST can help determine if the drive has a problem or not.

Regular Maintenance

Scheduling periodic long DST checks every 6-12 months will detect emerging bad sectors or mechanical issues. This allows you to replace drives before failure.

Critical Data Use

For drives being used for important data, verify functionality with a long DST first. This avoids entrusting unreliable drives with data you don’t want to lose.

Troubleshooting Issues

If you are experiencing unexplained crashes, file corruption, or data read/write issues, a long DST can pinpoint if the drive is the cause of the problem.

Running the long self-test regularly and at key occasions gives you ongoing monitoring of your hard drive’s health status.

How to Perform a Long DST Check

Hard drives provide built-in DST capability, but you need utility software to activate a manual start of the long self-test. Here are some options:

Windows – CHKDSK

The CHKDSK command line tool in Windows has a /R option that initiates a surface scan on the drive and repairs any bad sectors it finds.

To run an extensive check that maps bad sectors, use:

chkdsk C: /R

Replace C: with the letter of the drive you want to test. Add the /F option to fix any file system errors too.

Windows – Hard Drive Utilities

Most hard drive vendors provide utilities that give access to the DST functions. For example, Seagate’s SeaTools has a “Fix All” option that performs a long DST.

Linux – Badblocks

The badblocks command will do sequential reads of every sector and report any that fail to read. Use the destructive write test option to surface scan and overwrite bad sectors:

sudo badblocks -wsv /dev/sda

Drive Diagnostic Tools

Third-party diagnostics tools like Spinrite or HDD Regenerator offer comprehensive long DST testing features. They surface scan, remap weak sectors, and monitor drive health.

SMART Monitoring Tools

Utilities that read SMART data can initiate and monitor long DST checks. Examples include SpeedFan and CrystalDiskInfo.

Using any of these options provides a way to exercise the built-in long DST capabilities of your hard drive. Schedule and perform checks regularly for optimal drive health.

What Do Long DST Results Mean?

The long DST will take hours to run as it sequentially scans and tests every sector on the drive’s platters. When it finishes, you will get one of several outcomes:

No Errors Reported

A completed long DST with clean results indicates the hard drive is healthy and functioning properly. This is the ideal outcome.

Read/Write Errors Detected

If the DST surface scan encounters sectors that cannot reliably be read from or written to, the hard drive has bad sectors. A few may be repairable, but multiple errors indicate deterioration.

Failed/Aborted Test

If the DST ends prematurely or the tool indicates it failed, this points to serious hard drive malfunction. Critical hardware components may be damaged or defective.

Excessive Bad Sectors

More than a handful of bad sectors normally means the drive platter/heads have excessive damage. The device is beyond its serviceable lifespan and needs replacement.

Slow Test Execution

A significantly slower than normal DST process can indicate problems with the spindle motor or heads stalling. Have the drive checked for physical defects.

Analyzing the long test results helps determine the current health status of your hard drive and if replacement should be considered.

Benefits of Periodic Long DST Testing

Performing long DST checks on your hard drives at regular intervals provides these advantages:

Early Problem Detection

The DST will spot emerging bad sectors and mechanical defects long before they become catastrophic failures.

Prevent Data Loss

Identifying at-risk drives allows you to take preventative steps like copying data to a new drive before total failure results in data being inaccessible.

Monitor Drive Health Trends

Seeing the quantity and type of errors building up over time provides insight into the overall deterioration of drive hardware.

Determine Maintenance Needs

Based on DST results and health trends, you can decide when a hard drive is reaching end-of-life and needs to be replaced.

Confirm New Drive Integrity

Running an initial long DST on new hard drives ensures they do not have latent factory defects before you start using them.

Incorporating periodic long DST checks into your storage maintenance practices helps avoid unexpected failures and gives you time to take preventative measures.

Potential Long DST Check Issues

While the long diagnostic self-test is a valuable hard drive health check, some potential caveats exist:

No Repair of Bad Sectors

The DST will detect and log bad sectors but may not repair or remap them like dedicated repair tools can.

Additional Wear on Drive

Frequent long DST scans may incur more unnecessary platter/head wear on older drives if done excessively.

Read/Write Heads Unloaded

On some drives, the long DST unloads and parks read/write heads. This avoids checking those components.

No Detection of Intermittent Issues

Problems that come and go like temperature-related failures may not occur during a single long test.

Long Runtimes

The multi-hour run time for a full long DST on large high-capacity hard drives can be disruptive and time consuming.

Being aware of these limitations allows you to maximize the benefits of DST testing while minimizing any downsides based on your specific needs and situation.

Best Practices When Using Long DST

Follow these recommended practices when utilizing long diagnostic self-tests:

– Schedule tests during periods of low system usage to avoid disrupting active operations.
– Do not repeatedly scan older drives since lengthy tests may shorten remaining lifespan.
– Check event logs for recently logged drive errors before starting a long DST.
– Run long DST on new drives to confirm they are fully functional when installed.
– Consider using SMART tools to monitor DST status instead of running full manual tests repeatedly.
– Test secondary/backup drives as well as primary storage drives to uncover problems.
– If drive has visual damage, do not run DST as it risks further data loss – replace drive immediately.
– Determine if your specific drive heads are unloaded during DST and compensate accordingly.
– Combine long DST testing with other tools like CHKDSK for bad sector repair/remapping.

Integrating long DST checks wisely and judiciously provides maximum benefit for assessing and monitoring drive health.

Long DST Check Support By Manufacturer

Most enterprise and consumer hard drive brands integrate DST capabilities into their drives. Support for manually initiating long DST scans varies across vendors.


Seagate Drive Utilities include comprehensive long DST options ideal for drive maintenance. All models support extended self-tests.

Western Digital

WD Drive Utilities has a Data Lifeguard Diagnostic tool that lets users select custom extended test runtimes up to a full surface scan.


Toshiba’s HDD Diagnostic Tool supports both quick and extended drive self tests on all their popular storage models.


Samsung provides a Drive Diagnostic Utility that can perform basic or complete DST checks depending on user selection.


Most Hitachi drives work with the Drive Fitness Test (DFT) which includes short and long DST testing scenarios.

Check your drive manufacturer’s software downloads section to obtain the tools required for activating long DST checks on a given hard disk model.


Performing a long diagnostic self-test on a hard drive provides a comprehensive check of the drive’s physical integrity and health status. The extended surface scan detects bad sectors and mechanical defects that may not be found in a quick DST test. Running long DST checks at key occasions like new drive installation and as part of periodic maintenance routines allows early detection and prevention of failure conditions. While long DSTs incur some disk wear, the benefit of monitoring drive health trends over time generally outweighs the minimal impact. Used judiciously, incorporating long self-tests into a storage maintenance plan can help avoid catastrophic data loss and ensure your most important data is hosted on reliable healthy drives.