SMR v CMR – Which drives to add to Synology

SMR v CMR – Which drives to add to Synology DS416Play

Thanks for your useful videos. It would be great if you could help me with the following :

The use case :
I have had a DS416Play for just over 3 years and bought it with 2 WD60EFRX drives (CMR). I use it as storage for our family photos and music, and backup location for our various devices (laptops and phones).
The 2 drives are set up in 1 single storage pool in SHR configuration.

My objective :
I want to add 2 more drives and place them in a separate Storage Pool from the one with the 2 original drives (and set it up again in SHR configuration)
I would use the 2 drives to backup some data in the first storage pool.

The problem :
I just bought 2 WD 6TB Red drives that were supposed to be EFRX but turned out to be EFAX, and then I had to open the can of worms…

Since 2016, WD has replaced the 6TB Red drives with WD60EFAX drives (SMR) (as you covered in one of your videos)
Synology states that the EFAX models are not compatible with their DiskStations. But I have red stories online of people hat tried it and see no problem while many “experts” say to avoid SMR drives…

The dilemma :

– Should I keep the new WD60EFAX drives (as the EFRX appear to be End of Life) ? and have the second storage pool with SMR drives when the first one is with CMR drives. Is there really a compatibility issue ? can I mix SMR and CMR even if located in separate storage pools ?


– Should I try to find the older EFRX drives (hard to find) – Amazon states they will have some in stock soon even though it looks EOL (and return the EFAX drives)

– Or should I stick with CMR … and then either switch brand ? or go with a larger storage (for instance 8TB) as the WD 8TB Red are CMR.

What would you recommend ?


Yes, WD replaced the existing CMR range to SMR drives silently. This was very bad decision in ended up big Lawsuit Claims. I hope justice is served. But in the meantime, new SMR drives are NAS compatible but only recommended for users in the home environment or small business.

You should not mix CMR and SMR drives in the same RAID. But you can have two separate RAID on your Synology or Qnap NAS. If you can still find CMR drives on Amazon or eBay I would get them. Having a single RAID on a NAS gives more available storage space compared to several RAID groups. CMR drives will not be available for long since they are replaced.

If you do not trust WD you can have another RAID with Seagate drives.

A difference between CMR and SMR drives is speed and rebuild times. In home environment with 1Gbit network, you will unlikely notice a speed difference, and RAID rebuild times will be long anyway, adding few extra hours would not feel making a difference.


I hope this helps.


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