I've just bought a pro licence after using the free version for the last year or so, so the cache drive is new for me.

 

I've got it up and running fine, the problem is with user shares.

 

Is there a way to make an existing user share use the cache drive??

 

I have gone to my existing "Media" share and set "Use Cache Disk" to Yes. I assumed this would create a mirror of the share's file structure on the cache drive but the cache drive remains completely empty, I even rebooted to see if it was created after the next reboot or something.

 

I created a new test share just to check it was working and it was created on the cache drive, so the drive is installed and working properly.

 

Are you able to make existing shares use the cache drive?? Or will I have to create a new share and transfer all the data from the old share into it??

The cache is used when you write a new file to the share. It's use is completely automatic and transparent to the user. UnRAID will never move your data once written to the array.

There is also a mover script that is default set to move data off the cache drive nightly at 3:40am. Mover times can be changed as you like to more or less often & different times. Also if you are using any data from the share when the mover is scheduled, it may not run. I had XBMC open on another computer using my media share (which was partially on data drives & partially on my cache drive) the first night & nothing moved. The second night with nothing open / using the share, the files moved from cache to data (with parity) successfully.

 

Many more details on the cache drive & its uses can be found here http://lime-technology.com/wiki/index.php/Cache_disk

I had already read about the cache drive.

 

The confusion was coming from the fact that I was under the impression that the entire file structure of each share would be created on the cache disk when I selected "Use Cache Disk"

 

When this did not happen I was confused. However after now playing around with it and writing files into the share, I can see that the structure is only created as a file is written.

It's not clear that you understand the purpose of the cache disk!

 

When writing to an uncached share, both the parity disk and the data disk have to be read, then written - this takes time and makes writes to unRAID relatively slow.  The cache disk was introduced so that the apparent speed of writing was increased.  The write is performed to the cache disk, which doesn't require any pre-read - essentially writing as fast as the drive can accept the data.  However, this data has to be written to the parity-protected data disk later (the function of 'mover').  Until this 'move' is performed, you have no parity protection on that new data.

Yes I understand what the cache disk does.

 

Perhaps I am not explaining myself well.

 

I have a share called "MEDIA" inside that share are 2 folders called "MOVIES" and "TV" inside the "TV" folder is a folder for each tv show and inside them a folder for each season.

 

I was under the impression (after reading the wiki and the "Cache disk or not to cache disk" thread.) that the ENTIRE file structure of the share would be created on the cache disk. So I am expecting that when I checked the "Use Cache Disk" box on my "MEDIA" share that a folder called "MEDIA" would be created on the cache disk, inside that folder would be a "MOVIES" and "TV" folder and inside the TV folder would be a folder for each season - these folders would all remain empty until some new data comes along to be written to the array. Instead of being written to the array and parity calculated during the write, it would be written to the file structure on the cache disk and transferred by the mover script when it next runs. So if I transfer Falling Skies S02E04 to the array it would be written inside MEDIA/TV/Falling Skies/Season 2 folder on the cache drive and later transferred to the MEDIA/TV/Falling Skies/Season 2 folder on the array by the mover script.

 

The whole issue came from the fact that I am expecting to actually see the ENTIRE file structure of my share to appear immediately on the cache disk, instead the cache disk was empty. Hence why I started this thread.

 

After playing around with it I have now discovered that it only creates the file structure for the particular file that is being transferred. So transferring Falling Skies S02E04 creates a folder called "MEDIA" a folder inside that called "TV" a folder inside that called "Falling Skies" and a folder inside that called "Season 2" and nothing else.

 

 

Once mover has run (and moved the files to the array) the created folder structure will disappear.

Once mover has run (and moved the files to the array) the created folder structure will disappear.

Not on version 4.7. The empty structure remains. I can't speak to later versions.

Once mover has run (and moved the files to the array) the created folder structure will disappear.

Not on version 4.7. The empty structure remains. I can't speak to later versions.

Directory structure is removed on all versions.

Once mover has run (and moved the files to the array) the created folder structure will disappear.

Not on version 4.7. The empty structure remains. I can't speak to later versions.

Directory structure is removed on all versions.

When is this supposed to occur? My cache drive has always had empty directories on it, I periodically go in and manually delete them.

I was mistaken. The directories do remain.

The directories are removed on my 4.7 server. The directories did remain up to the versions fairly recently before 4.7.

 

I need to revise my statement. My cache drive folders are not empty running 5.0rc5. They contain a hidden .Apple directory that is written on every access. I think directories are normally removed, but the hidden Apple files keep the directory on the cache disk. I would not manually remove the directories.

Directories should be removed, even in 4.7- provided that they are empty. To check, use:

 

cd /mnt/cache

ls -aR

 

root@Tower:/# cd /mnt/cache
root@Tower:/mnt/cache# ls -aR
.:
./  ../  test/

./test:
./  ../  .test.txt*

 

This shows the hidden file (.test.txt) in the directory (/mnt/cache/test)