QNAP® Systems, Inc. has started releasing the QTS 4.3.3.0210 Build 20170606 update to users. After installing the update, scheduled RAID Scrubbing will be automatically enabled on QNAP NAS (if not already enabled by users) to increase the integrity of user data, and to proactively ensure the security of disk groups.

RAID Scrubbing is used to verify the data integrity of disk groups with RAID 5 and RAID 6 configurations. It works by running a redundancy check to detect and correct inconsistencies that are undetectable during routine usage. Periodically running RAID Scrubbing can detect potential corrupted data or disks at an early stage, giving your NAS the chance to attempt automatic repairs or to report disk-related issues, helping to ensure the integrity of user data and disk groups.

RAID Scrubbing runs in the background with minor performance impact (depending on storage space sizes). QNAP recommends running RAID Scrubbing weekly or monthly, according to access frequencies of data stored in the NAS. Users can configure RAID Scrubbing settings in "Storage Manager" > "Global Setting" > "Data Scrubbing".

To learn more about RAID Scrubbing, please check:
https://en.wikipedia.org/wiki/Data_scrubbing