NX2/ZX systems use ZFS for the file system. ZFS file systems have the ability to run a scrub scanner, the scanner is a maintenance operation that helps ensure the data integrity of the file system.
Running a scrub is a key feature of ZFS and serves the following purposes:
Data Integrity Verification: ZFS scrubbing scans the entire pool, including all the data and metadata stored on it. During this process, it reads all the blocks and verifies their checksums. If any block is found to have a checksum mismatch or other data corruption, ZFS attempts to repair it using redundancy information (if available) or reports the error.
Early Detection of Silent Data Corruption: Silent data corruption, also known as "bit rot," can occur over time due to various factors such as disk errors, cosmic rays, or other hardware issues. By regularly scrubbing the ZFS pool, you can detect and correct these issues before they become a serious problem.
Ensuring Data Availability: Scrubbing helps ensure that all the data on the pool is accessible and correct. If a corrupted block is detected during the scrub, ZFS will attempt to recover the data from redundant copies (if configured with RAIDZ or mirrors) and replace the corrupted data.
Preventing Data Loss: Regular scrubbing helps prevent data loss by identifying and fixing potential issues before they can lead to catastrophic data loss.
In short, running the scrub scanner on your NX2/ZX pool is a crucial maintenance task to help verify the integrity of your data, help prevent data corruption and loss on your NX2/ZX storage system.
How to run the scrub scanner?
A lot of the times when a drive is producing errors in the NX2/NX3/ZX systems GUI a Scale Logic Tech will ask you to clear the error counters for the drives and run a scrub scan. This is done to verify the drive actually has errors, the ZFS filesystem cannot tell a lie so it will report every error the drive see's even though the drive may have corrected the error itself. Once the error counter has been cleared and new scrub ran the Tech will want a new set of support logs to review to determine if the drive really should be replaced or not.
- To run the scrub scanner on your system you will need to login to its Web GUI.
- Once logged in find your "Pool" and click on the "Options" menu and choose "Clear error counters"
- Once the error counter is clear please go ahead and start the scrub scan, the time it takes for the scrub to complete depends on the size of the data on the system.
- Once the scrub is complete please gather a new set of logs, upload it to the Scale Logic fileshare and respond to the case letting the Tech know so they may review the new set of logs to determine if the drive really needs to be replaced or not.
Fileshare to upload logs