I am thinking about replacing my cache drive with an SSD (probably the Crucial MX100 256GB).  I know that unRAID does not support TRIM so the drive must rely on built-in garbage collection by the SSD.  I use the cache drive for apps including Plex.

 

For those using an SSD for the cache drive, does Plex allow GC to work?  My current mechanical cache drive rarely (if ever) spins down, and this seems to be due to Plex.  GC requires the SSD to be idle for a good period of time?

 

 

 

Bump.  No one using an SSD for their cache drive and running Plex on it?

 

 

While I do generally understand your question, the specifics are a bit ... off.

 

What would you expect Plex to be doing to prevent GC?

 

Plex does indeed keep a drive "awake" due to it constantly writting to the log file. That is why I have an SSD holding plex (technically now my entire VM with plex inside it) but it is also not my cache drive. It is a drive "outside" the array while I still maintain a spinner as my cache.

 

A benefit to this is that you can get TRIM support by formatting as ext4 and mounting with the DISCARD parameter.  The SNAP plugin works great for this.

 

Beyond that, I see no reason your drives GC should be impacted unless it is a very poorly implemented GC.

I think he means that drive based GC only kicks in when the drive is idle.

 

Therefore if plex is constantly writing to a log, it may never kick in.

Yes, that is my concern.

 

I don't have room in the case for separate apps and cache drives, so using an SSD for an apps drive with ext4 and TRIM enabled is not an option.

 

I wouldn't worry about it. Plex isn't writing, literally, constantly. But with respect to most spin-down settings people use, it will keep a drive from ever spinning down. But there should be enough time for a decent GC process to do its job.

 

Alternatively you could upgrade to 6.0 beta, format the cache as XFS or BTRFS

 

 

Thanks, I went ahead and ordered the SSD. 

 

Glad you mentioned brtfs in 6.0 beta.  I have not been following all the 6.0 threads.  I did a quick search and seems with brtfs I can mount the SSD with -o discard or periodically run fstrim.