How is a WORM retention period counted in QuTS Hero and QES?

Applicable Products

QuTS hero, QES

Background

WORM (write once read many) technology ensures that once data is written, its state remains unchanged. The data cannot be deleted or modified, effectively locking the data state. WORM is primarily used for long-term data preservation or compliance applications, as well as for cybersecurity protection against ransomware encryption.

One of the WORM settings you can configure is the WORM retention period. This period determines how long WORM applies to the files and folders in a WORM shared folder. 

Details

A WORM retention period is not based on system time, but instead based on the uptime of the storage pool that contains the WORM shared folder. 

Each storage pool has its own WORM clock that determines when a WORM retention period ends. The following situations may pause the WORM clock:

• Shutting down the system
• Restarting the system
• Detaching the storage pool
• Detaching a disk in the storage pool
• Detaching the enclosure that contains the storage pool
• Locking the storage pool if the pool is an SED secure storage pool
• Updating the NAS firmware
• When the number of abnormal disks in the storage pool's RAID group exceeds the RAID group's disk failure tolerance

When any of the above events occurs, the WORM clock automatically pauses. The WORM clock only resumes when the interrupting event ends or returns to a normal state. However, due to the pause, the WORM retention period would end up finishing later than the specified duration.

Example

1. A WORM shared folder is created with the retention period set to 3 days (72 hours). 
2. A file is added to the WORM shared folder on Monday 18:00.
   • If there are no events that cause the WORM clock to pause, the WORM retention period for the file would be expected to end after 72 hours on Thursday 18:00.
3. The NAS shuts down on Tuesday 01:00.
   • The WORM clock pauses.
4. The NAS starts up on Tuesday 06:00.
   • The WORM clock resumes.
   • The last 5 hours are not counted as part of the WORM retention period for the file.
5. No further events cause the WORM clock to pause.
6. The WORM retention period for the file ends on Thursday 23:00. 
   • The file can now be modified or deleted.
   • The end time is 77 hours after Monday 18:00 when the file was added to the WORM shared folder. 
   • The 77 hours include:
     • 72 hours that the WORM clock counted when the NAS was running
     • 5 hours that the WORM clock paused when the NAS was shut down

WORM Limitations

• WORM can only be enabled during shared folder creation. 
• WORM cannot be enabled or disabled after shared folder creation.
• WORM settings cannot be modified after shared folder creation, except for the following:
  • The WORM retention period can only be modified after shared folder creation if the WORM type is set to "Enterprise". 
• When cloning from a snapshot of a WORM shared folder, WORM will be disabled in the new shared folder.
  The WORM settings of the original shared folder are not cloned to the new shared folder.

Further Reading

• Why am I still able to delete files in a WORM shared folder?
• What is the difference between Enterprise and Compliance WORM?
• Can I copy or move items into a WORM folder?