Cache Drive: SMR versus CMR? Desktop class versus NAS?

[Jaybau]

SMR versus CMR drive for cache?  

Desktop/laptop class versus NAS class for cache?

 

The #1 reason why I am considering a desktop/laptop SMR drive is because I can get it in 2.5" size, and I don't have enough 3.5" bays available.  

 

I have a SSD drive for dockers/VM's.  But I don't want to wear out the SSD drive just to temporarily cache data before moving to the protected array.   I also use the drive for downloading torrents, which do frequent tiny read/writes and don't want to wear out a SSD.  The drive's speed only needs to be as fast as my 1G network; I don't need the speed when data is moved to the array.

 

SMR
+++ 2.5" drive slot
+ More load/unload cycles
+ Quieter
++ Less heat = last longer (but over lapping might mean it doesn't last as long)
+ Cheaper (but not by that much on small drive)
+- Slower (but fast enough)

 

The one problem SMR might have is filling up the drive's cache and multiple read/writes on pre-written files (over lapping?).  However, I don't expect the unraid cache drive to fill up since data is moved to the array nightly, so not sure if over lapping will be an issue.

 

The next concern I have is that 2.5" SMR drives are considered "desktop" class, and that could mean they aren't meant to operate 24x7 in a home NAS, and there could be load/unload cycle issues.

 

My use is a home media NAS, which isn't a "deskop" and not "enterprise 24x7".  

 

Thoughts?