First off, my appologies if this is in the wrong place. Its more of a 'Am I going to break it' thread rather then direct unraid support.

 

I currently have a couple of downloaders installed (sabnzbd, sickbeard) on the cache drive to allow for downloads direct to the server rather then keeping my main watercooled PC on 24/7 (bit of a power waste). This works fine and has for a could of years but I was having a little think about it the other day. The cache drive doesn't spin down due to the software which is running on it always keeping the drive spinning. I don't know the reasons behind this but I've seen it several times on a few forums.

 

My idea for a solution was to maybe add a USB memory stick to the server as an 'application' drive so the downloaders can run from the USB which would hopefully allow the cache drive to spin down like the others saving a bit of power - then only spin up again when a download action takes place.

 

Is there any reason you can think why this wouldn't work or is a flawed idea?

Either that or maybe consider using a SSD as your cache drive... faster and much less power!

Well t be honest I don't copy much data from other sources I the server - most data is downloaded on the server so the money to invest in a SSD is high compared to the usefulness. I might look at it if I upgrade my PC SSD setup but for now I get 30-40mb/s transfer from my PC and I generally only copy a couple of a GB at a time so it's not a huge issue.

 

How much real world difference is a SSD making to transfer speeds over gigabit networking?

You're really worried about 10W of power usage for 1 idle drive? (approx 88KWh / year or less if its a green drive).  For the price/performace of a HDD I would stick with using the cache drive (not on a SSD or USB).

 

If you are worried about power usage: you should look at putting the entire system to sleep.  Just my 2c

 

If you will use a USB drive as the application drive you run the risk of "killing" it due to the high write count the applications might cause.

 

 

Thanks for the replies.

 

It's not a case of being worried about the 10w, it's more a 'if I can save the 10w, why not' - it's not like I'm loosing sleep over it or anything

 

I'm also looking into S3 sleep and WOL but haven't played with it before so it will be a first venture into it.

 

I did wonder about the writes to a USB stick - are CF cards rated for a higher write cycle?

 

I've got a kingstone 16GB SSD spare so I guess I could proof test the setup with that and look at a SSD investment if needed. I would guess given the max network speed I'm going to get isn't you to touch sata2 SSD write speeds a older gen SSD like a Vertex 2 would work just fine

Put your watch folders in RAM!!

 

It this your cache drive will spin-down