SATA SSD's - Are Disk Scrub and Disk Test necessary?

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jimk1963 wrote:

RN528X, freshly repopulated with 8 Crucial 4TB MX500 SATA SSD's. 

 

With guidance from StephenB , I set up the NAS to perform each of the 4 Maintenance tasks once per quarter (Scrub, Disk Test, Defrag, Balance). This was with spinning HDD's initially.

 

Question: with SATA SSD's, is it advisable or not advisable to run all 4 of these maintenance tasks on this schedule? 

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is there anything "electromechanical" about the HDD's that makes them need these tests but SSD's do not?

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Getting back to the main questions: 

• Defrag has marginal value even with mechanical disks.  SSDs have 0 seek time, so you could just turn this off.  You can always run it manually.
• I'd run the disk test, as it doesn't effect endurance.
• Balance reclaims/consolidates optimizes BTRFS free space.  It will do some writes, but I'd run it anyway.  On my systems, it usually completes in less than 45 minutes.
• Scrub is the unknown.  If it does rewrite all the parity blocks (which would be the worst case), then you'd be writing 25% of each disk with RAID-6, and 12.5% of each disk with RAID-5.  Assuming RAID-6, you'd be writing 1 TB per drive every time you run it.  The endurance rating for the MX500 4 TB model is 1000 TB.  Overall the effect is relatively small (less than 0.4% reduction in disk life per year).  I'd probably choose to run it, but I guess you could reduce the frequency.