I've noticed that none of the drives in my array will spin down while I'm running preclear on a drive.  Is this normal?

 

I've noticed that none of the drives in my array will spin down while I'm running preclear on a drive.  Is this normal?

 

Nope.

 

However, if you have other processes (on PCs on your LAN) that are scanning shared drives and are expecting that normally the contents they expect are in the disk buffer cache, they'll need to spin up the respective disk instead.

 

The cache is being used as fast as it can for the pre-clearing reading and writing.  If you are clearing a 1TB drive you would need over 1TB of memory for everything read to be kept in memory.  (and odds are REALLY GOOD you do not have 1TB of RAM)  The least recently used blocks are being re-used, and since the clearing process reads and writes every disk block, it is the most recently used set of blocks.

 

So, it it likely it is just other programs (from your LAN connected PCs) scanning your shares that are keeping the disks spinning, because their directory contents must be read from the disks themselves, since it is not in the disk buffer cache.

 

Joe L

Cache_dirs must be the culprit then.  Makes sense - thank you.

Cache_dirs must be the culprit then.  Makes sense - thank you.

It is not a culprit, it is doing its job.  ;D  The directories are not in the disk cache, so it must spin up the drives to read them.

 

Joe L.

Cache_dirs must be the culprit then.  Makes sense - thank you.

It is not a culprit, it is doing its job.  ;D  The directories are not in the disk cache, so it must spin up the drives to read them.

 

Joe L.

 

Then I don't know what it could be as there is nothing external accessing the unRAID server.  All else staying the same the drives spin down roughly 60 minutes after the preclear finishes.  Oh well, I'm not going to sweat it - I don't run preclear that often.

Cache_dirs must be the culprit then.  Makes sense - thank you.

It is not a culprit, it is doing its job.  ;D  The directories are not in the disk cache, so it must spin up the drives to read them.

 

Joe L.

 

Then I don't know what it could be as there is nothing external accessing the unRAID server.  All else staying the same the drives spin down roughly 60 minutes after the preclear finishes.  Oh well, I'm not going to sweat it - I don't run preclear that often.

You did not understand.  It IS cache_dirs accessing the drives, because it HAS to, because the data it is trying to keep in the cache so you can spin down disks is being displaced by the pre-clearing process rapidly using the same pool of cache.

 

Live with it, or turn off cache_dirs, and live with the fact that when you browse to the server with your media players you have to wait for the disks to spin up.

 

Joe L.

Joe, maybe in preclear it could offer to turn off cache_dirs while it is running. Just a suggestion, I'm likely to forget to do it myself and that will keep everything spun up for a long time.