How do I check and monitor RAID scrubbing process on my QNAP NAS?

Last modified date: 2026-02-13

Applicable Products

All NAS models running QTS or QuTS hero

Scenario

You start a RAID scrubbing (data consistency check) task from the NAS GUI.
In an SSH session, running ps -ef does not show any obvious process named scrub or similar.
You want to detect via script whether RAID scrubbing is currently running, but cannot identify a dedicated user-space process.

Procedure

For advanced users: This article involves SSH access and command-line operations. Incorrect commands or changes to system files may cause service disruptions or system instability. Proceed only if you are familiar with these operations and have recent backups of important data.

Step 1: Enable SSH

Log in to QTS or QuTS hero with an administrator account.
Go to Control Panel > Network & File Services > Telnet / SSH.
Select Allow SSH connection.
Set the port number (default: 22).
Click Apply.

Step 2: Connect to the NAS using SSH

Use PuTTY (Windows) or Terminal (macOS/Linux) to connect to the NAS:

ssh admin@<NAS_IP>

Step 3: Check and monitor the RAID scrubbing process

QTS (md-RAID)

On QTS systems that use Linux software RAID (md-RAID), you can check the RAID scrubbing status by reading /proc/mdstat.

Run the following command:

cat /proc/mdstat

If RAID scrubbing is in progress, you will see a line similar to the following for the affected RAID group:

md1 : active raid5 sda3[0] sdb3[1] sdc3[2]
      [==>........]  check = 15.3% (12345678/98765432) finish=120.0min speed=123456K/sec

You can also check and monitor the scrubbing process using the following command:

ps -ef | grep resync | grep -v grep

If RAID scrubbing is in progress, you will see a process line similar to this:

21984 admin           DWN [md1_resync]

Key points:

The percentage and estimated time in /proc/mdstat show the current progress.
The md1_resync kernel thread indicates that a RAID resync or scrubbing process is in progress.
If no such operation is listed, RAID scrubbing is not currently running.

QuTS hero (ZFS)

On QuTS hero systems that use ZFS, you can check the scrub status of a storage pool using zpool status.

Run the following command:

zpool status <pool_name>

If a scrub is in progress, you will see output similar to:

  pool: pool1
 state: ONLINE
  scan: scrub in progress since Mon Feb 12 10:00:00 2026
        15.3% done, 1h20m to go
config:

        NAME        STATE     READ WRITE CKSUM
        pool1       ONLINE       0     0     0
          ...

If no scrub is running, the output will show the time of the last completed scrub or a message such as:

  scan: scrub repaired 0B in 01:23:45 with 0 errors on Mon Feb 12 09:00:00 2026

You can use this information in scripts to detect whether a scrub is currently running and to monitor its progress.

Applicable Products

Scenario

Procedure

Step 1: Enable SSH

Step 2: Connect to the NAS using SSH

Step 3: Check and monitor the RAID scrubbing process

QTS (md-RAID)

QuTS hero (ZFS)

Further Reading