Hey guys

 

I've recently found a 500GB hard-drive that's been hiding in a USB enclosure since I last moved house. I'm pondering here if I should toss it into my UnRAID as a cache disk.

 

This is partially because I have noticed that directing big downloads directly to my UnRaid box seem to cause both the disk I'm downloading to and the parity drive to be constantly spun-up and thus drawing power and creating heat. Normally this wouldn't be a problem but my set-up is a little under-ventilated and being constantly writing pushes the temp on my parity drive over the level I'm comfortable with.

 

So, if I put in a cache drive and direct my downloads to \\tower\cache this should stop my parity drive needing to constantly be writing, and only spin-up when the cache drive drumps into the main array, correct ? If not, can someone point me in the direction of how to do that ?

 

I know I'm never going to genuinely NEED 500gigs of cache, but its the drive I have to hand and I'd be happier getting some use from it (assuming it will do what I want) rather than an extra 500gigs of which feels somewhat redundant in my 10TB array.

 

On a completely unrelated topic (but since I'm posting anyway) UnMenu keeps telling me I have duplicate files, and I have no idea what you are supposed to do about that other than the long and painful process of manually deleting each file... Anyone know of a script or add-on that can remove duplicate files for me ?

I just finished setting up my first unraid box and I put in a 500gb disk as a cache drive because I simply had one laying around in an enclosure

 

All you have to do is add it as a cache drive, and then under each user share, you will have a new setting asking you about enabling the cache drive for that share.

 

For instance I set up my movies share to use a cache drive. Whenever I copy something to the movies share on the unraid box, it actually puts the files on the cache drive first, and then overnight, mover script moves it over to the array disks.

 

While the files are on the cache drive, they still do appear in your movies share. So from an end user's perspective you can't tell whether the file is on the cache drive or the array unless you mount the drives and check for the contents. It is completely automated.

 

For scripts that write files to the array such as sabnzbd, you don't have to change anything in their settings. As long as the user share is set to use a cache drive, sab downloads will go to the cache drive first.

 

The mover script by default runs at 3:40am every day, but you can change that. That way, I minimize writes to the array and the parity drive. (As you know, sab not only downloads, but also extracts, sometimes multiple levels and each extraction is another full write process. This way, all those are handled at the cache drive and the final files are written to the array once and all at once)

 

 

There is one disadvantage worth mentioning though, while the files are on the cache drive, they are not parity protected. So make sure you preclear your cache drive at least three times before adding :-)

A cache drive is useful for many situations, but I have to speak frankly and say..

If you are having concerns about temperature , you should be addressing those directly with a solution that resolves the root condition.

If you ever have a drive failure, you will require all the drives to be spinning in order to recreate the failed drive.

Your temperature is sure to spike then. You will need to prepare for that condition as it's only a matter of time.

It's not IF a drive will fail, it's only a matter of WHEN.

On a completely unrelated topic (but since I'm posting anyway) UnMenu keeps telling me I have duplicate files, and I have no idea what you are supposed to do about that other than the long and painful process of manually deleting each file... Anyone know of a script or add-on that can remove duplicate files for me ?

The easiest way to take care of duplicates is to rename the folder that contains the dupes by adding an additional letter or something. Then you can run something like http://www.clonespy.de/ from a windows machine on the two folders.

Fix your cooling problems. Even if you never rebuild, you should still be doing regular parity checks.

 

Never write to /mnt/cache. Set the shares to use the cache and write to the shares, which will then automatically include the cache.

 

Set a minimum free space size for the cache disk bigger than any single file size so you don't acidentally fill it and get an error. If it's full, things automatically revert directly to the array.

 

I have no idea about the dupe files but you should figure out how you managed to do that and stop it in the future.

 

Peter