Data Scrubbing

Data scrubbing is a data maintenance feature that amends data in storage pools that are incorrect or incomplete. We recommend performing data scrubbing periodically to ensure data consistency and avoid data loss in the event of a drive failure.

Before You Start

  • Data scrubbing is only supported on Btrfs volumes or storage pools of the following RAID types: SHR (consisting of three or more drives), RAID 5, RAID 6, or RAID F1.
  • If the option data checksum for advanced data integrity is not enabled for a shared folder (at Control Panel > Shared Folder > Edit > Advanced), data scrubbing will not be able to check and repair the data in the folder because of a lack of checksums.
  • Scheduled data scrubbing will be stopped if your Synology NAS was shut down improperly during data writing, but will resume automatically once your Synology NAS is powered on again.

Perform or Schedule Data Scrubbing

You can run data scrubbing immediately or on schedule depending on your needs.

To run data scrubbing right away:

  1. Go to the Storage page.
  2. Click the storage pool on which you want to perform data scrubbing.
  3. Click Run Now under the Data Scrubbing section.
    Note: The section is unavailable if the selected storage pool does not support data scrubbing.

To run data scrubbing on schedule:

  1. Go to the Storage page.
  2. Click the Schedule Data Scrubbing button.
  3. Tick the Enable data scrubbing schedule checkbox.
    Note: Only storage pools that support data scrubbing can be added to data scrubbing schedules.
  4. Select and prioritize the storage pools that you want to perform data scrubbing.
    Note: Data scrubbing can only run on one storage pool at a time.
  5. Set the schedule for running data scrubbing:
    • Frequency: Select how often you want data scrubbing to run from the drop-down menu. For example, repeat monthly or repeat every six months.
    • Set Time Grid: Set a specific time for running data scrubbing to prevent the system performance from being affected at a certain time.
    • Next run time: This field shows the date and time of the next scheduled data scrubbing.
  6. Click Save.

Note:

  • The status of the storage pool will change from Healthy to Running data scrubbing during the data scrubbing process and will change back to Healthy once the process is complete.
  • If a data scrubbing schedule is already set in DSM 6.1 version, then the schedule will still be applied to the upgraded version automatically.

To learn why data scrubbing cannot be performed on a specific storage pool:

  1. Go to the Storage page.
  2. Click the Schedule Data Scrubbing button.
  3. The storage pools on which data scrubbing cannot be performed will be listed at the bottom of the Schedule Data Scrubbing window along with the reasons (e.g., incompatible file systems, incompatible RAID configurations, and abnormal storage pools).
    Note: A degraded storage pool will be temporarily removed from data scrubbing schedules, and will be automatically added to the schedules once the storage pool has been repaired. However, a crashed storage pool will be permanently removed from data scrubbing schedules.

To pause data scrubbing:

Performing data scrubbing may take some time, and you can manually pause it when needed.

  1. Go to the Storage page.
  2. Select the storage pool on which data scrubbing is running.
  3. Click the upper-right icon to expand the storage pool information.
  4. Under the Data Scrubbing section, click the Pause data scrubbing button. If the task runs by schedule, click the Pause Schedule button.

Note:

  • If a schedule is paused, you must click Resume Schedule to resume it; otherwise, the schedule will remain paused.

Modify the Data Scrubbing Schedule

To view the data scrubbing schedule:

After you have enabled data scrubbing and set its schedule, you can go to Overview > Task Schedule to view its status and run time. You can also do the following to view the information:

  1. Go to the Storage page.
  2. Select the storage pool on which data scrubbing is running or is scheduled to run.
  3. Click the upper-right icon to expand the storage pool information and view the data scrubbing information.

To add or remove a storage pool from the schedule:

You can add or remove a storage pool from the data scrubbing schedule by doing the following:

  1. Go to the Storage page.
  2. Click the Schedule Data Scrubbing button.
  3. Tick or untick a checkbox to respectively add or remove a storage pool from the schedule.
  4. Click Save.

Note:

  • If you remove a storage pool that is undergoing data scrubbing, then the data scrubbing process will be canceled.

To modify the data scrubbing schedule:

After the data scrubbing schedule is set, you can still modify it by doing the following:

  1. Go to the Storage page.
  2. Click the Schedule Data Scrubbing button.
  3. Change the frequency and time grid according to your needs.
  4. Click Save.

Note:

  • If you modify the schedule, the system will cancel the data scrubbing in progress and perform it again according to the updated schedule.
Before You Start
Perform or Schedule Data Scrubbing
Modify the Data Scrubbing Schedule