Cache drive cannot be spun down

[K O]

Problem: The write speed to the cache drive has dropped to 2.5MB/second - basically abysmal. 

 

Background: I have been using an OCZ Vertex Plus 128GB SSD as my cache drive and allowing Unraid to serve as my storage space for SageTV to record TV shows (up to 5 at a time plus real-time commercial detection).  Currently running Unraid 5.0RC10 with no other issues.  I have removed all plugins except for a few Simple Features plugins.

 

Solution: The drive supports background garbage collection, but only when the drive is not in use (e.g. spun down).

 

Catch: Unraid will not allow the drive to spin down, even if I give it the hdparm command to spin down.  I modified the spin down for the cache drive to be 15 minutes, but it still doesn't spin down, even when nothing is being used.  I've also removed the cache drive from being used by any shares, and it still won't spin down.

 

How do I get the SSD to idle so that it can run its background garbage collection?

[BetaQuasi]

SSD's don't spin down, so what you are seeing is as expected.  They don't have any moving parts, so the whole 'spin down' concept doesn't apply to them.

 

The real question is what else is using your cache drive in terms of plugins etc that may keep on writing to it?  Idle time for garbage collection is simply defined as time where nothing is reading to or writing from the drive.  This should occur on a regular basis unless you have a plugin or similar that is constantly thrashing your cache drive.

[K O]

I understand that SSD's don't have any moving parts.  Unraid always shows it as 'spun up'.  The cache drive isn't associated with any shares and the Unraid server is unused/idle for more hours of the day than not.  The plugins I have installed are the following version 1.05 Simple Features plugins:

 

[*]Active Streams

[*]Activity Monitor

[*]Web GUI

[*]Disk Health

[*]Email Notify

[*]Log Viewer

[*]System Info

[*]System Stats

[Joe L.]

I understand that SSD's don't have any moving parts.  Unraid always shows it as 'spun up'.  The cache drive isn't associated with any shares and the Unraid server is unused/idle for more hours of the day than not.  The plugins I have installed are the following version 1.05 Simple Features plugins:

 

[*]Active Streams

[*]Activity Monitor

[*]Web GUI

[*]Disk Health

[*]Email Notify

[*]Log Viewer

[*]System Info

[*]System Stats

I'd type lsof to see if files are open on it.

[K O]

I ran lsof, and while I don't really understand everything I'm looking at, there were no instances of 'sda' in the output.  My cache drive is currently mounted as /mnt/sda.

 

A copy of everything from lsof is attached

lsof.txt

[K O]

Update: It's definitely not getting a break from Unraid.  I detached it as the cache drive for 24 hours, and it looks like the garbage collection finally ran - at least somewhat.  I re-attached it as the cache drive and associated it with a share.  Write speed is back up to +/- 60 MB/sec, which is greatly improved over 2.5 MB/sec, but still not like when it was new.

 

The problem remains though, why wouldn't the cache drive ever get to idle?  I can't remove it from the array every day to let it run garbage collection.