Content remains on cache for NON-cache enabled shares

[rragu]

Running on 6.8.1

 

I have an unRAID server at my parents' house, mainly because they have gigabit FiOS and I don't (for the same price as my 200Mbps, I might add; but that's a rant for another day). 

 

I live in another city and I usually use Syncthing to add any content from my personal desktop to the unRAID server. I then use Krusader to move content from the Syncthing share to whatever share it needs to go into. 

 

I have noticed though that when I transfer content from the Syncthing share (which is cache-enabled) to, for example, my Media share (which is NOT cache-enabled), the content nevertheless remains on the cache drive. And since the Media share is not cache-enabled, the content never moves to the array even when Mover is invoked in the early morning. Now, I suppose that I could wait for Mover to move the content from cache to array within the Syncthing share first and then move to Media. But, that could take up to a day and I'm impatient. 

 

So my question is: is this expected behavior or do I have some incorrect settings in place?

[BRiT]

Somewhat expected, depending on how you "transfer content" from one share to the other.

 

Mover does not move files from cache to disk for shares set as use cache: no.

Mover does not move files from cache to disk for share set as use cache: prefer.

 

[remotevisitor]

This is expected behaviour .... but the reason is rather subtle.

 

The cache setting on a share is used when a file is created on a disk.   So when you use Syncthing to copy the files to your system it is creating new files on your system so it honours the cache setting and creates the files on the cache disk.

 

When you then move the files to your Media share it is just renaming the files (not creating new files) so the cache setting is not used and the files will remain on the cache disk.     As the Media share cache setting is "No", mover does not move files from the cache disk.

 

So you currently have 2 possibilities:

• Change the cache setting on your Media share to “Yes" so that mover will copy files from cache disk to data disks.
• Copy the files to /mnt/user0/Media rather than /mnt/user/Media;  this will ensure the moved files are moved to the data disks rather than remain on the cache disk.  (Note however Tom is thinking about removing /mnt/user0 in a future version).

- 

[rragu]

11 minutes ago, BRiT said:

Somewhat expected, depending on how you "transfer content" from one share to the other.

 

Mover does not move files from cache to disk for shares set as use cache: no.

Mover does not move files from cache to disk for share set as use cache: prefer.

 

Syncthing is set to cache: Yes

Media is set to cache: No

 

According to the tooltip in the Share Settings page, "No prohibits new files and subdirectories from being written onto the Cache disk/pool."

So if (1) content is on the Syncthing share and the cache drive and (2) I then move it to the Media share using Krusader, my expectation is that content moves from Syncthing share on the cache drive to the Media share on the array (bypassing the cache drive since Media is NOT cache enabled).

 

But that doesn't seem to happen. When I check the cache drive contents, there is a Media folder on the cache drive with the contents I just transferred.

 

EDIT: I just saw @remotevisitor's explanation above

Edited January 26, 2020 by rragu

[rragu]

2 minutes ago, remotevisitor said:

This is expected behaviour .... but the reason is rather subtle.

 

The cache setting on a share is used when a file is created on a disk.   So when you use Syncthing to copy the files to your system it is creating new files on your system so it honours the cache setting and creates the files on the cache disk.

 

When you then move the files to your Media share it is just renaming the files (not creating new files) so the cache setting is not used and the files will remain on the cache disk.     As the Media share cache setting is "No", mover does not move files from the cache disk.

 

So you currently have 2 possibilities:

• Change the cache setting on your Media share to “Yes" so that mover will copy files from cache disk to data disks.
• Copy the files to /mnt/user0/Media rather than /mnt/user/Media;  this will ensure the moved files are moved to the data disks rather than remain on the cache disk.  (Note however Tom is thinking about removing /mnt/user0 in a future version).

- 

Ahh I see. That makes more sense. 

 

Yeah I think I'll just set Media to be cache-enabled. I had worried about unnecessary writes on the cache disk. But, I believe SSD drive endurance is high enough now that I'm more likely to replace the drive due to obsolescence before failure due to endurance

[itimpi]

2 minutes ago, rragu said:

Ahh I see. That makes more sense. 

 

Yeah I think I'll just set Media to be cache-enabled. I had worried about unnecessary writes on the cache disk. But, I believe SSD drive endurance is high enough now that I'm more likely to replace the drive due to obsolescence before failure due to endurance

Yes that is probably easiest.    You are not really increasing the wear measurably on the SSD as a rename is only a single I/O operation that just updates a directory entry.