Disks won't spin down

[bradlewa]

I installed an Ubuntu VM on my machine to enable a VPN service to route all my web traffic through (basically using the spaceinvader1 tutorial). This was ~30 days ago. Now every time I login to my server, all of the disks are spun up all the time. First question is whether this is bad for the drives...I know it uses more energy, but is it bad for disk life, etc. Second question is whether its bad for disks or not, what can I do to get the disks to spin down again.  I assume its the VM that caused this.  Thanks!

[Ascii227]

Disks being left on 24/7 vs disks being spun down is an age old debate which has no right or wrong answer. Some people will tell you that Spinning up and down a disk adds unecessary physical movement and therefore extra wear. Other people would argue that the time spun down greatly offsets this negative by providing you with many more hours of disk use within the manufacturers spec and the power/money saved over time. At the end of the day you should look at your own hardware and use case and make an informed decision. Things like drive ratings, ambient temperature etc can all have an effect. For example, I spin my disks down because if I leave them all spinning 24/7 a lot of heat builds up in my case leading to their temperature rising above the manufacturers recomendations, and therefore causing premature wear and warranty voiding.

 

Do you have 24/7 rated drives like WD Reds, or Seagate Constellations? If so they are rated to be left on and in use continuously for years so you should have no problem staying spun up all the time. If you have more consumer level drives like WD Blues then maybe letting them spin down is a good idea. Consumer operating systems such as windows and Mac OS spin down their drives by default to save power and expand life, so its probably best to follow suit if you are not sure yourself.

 

My guess would be that since you have created a VM, the libvirt iso along with your VM image and disk are being stored on the array which is causing it to never spin down as the VM always needs access. My advice would be to leverage the caching system (Set the System and Appdata share cache settings to Prefer) or install another seperate SSD mounted with the unassigned devices plugin, and move your VM related files there. This way it will run fully from that single drive, and never touch your array leaving it to spin down after use.

 

TLDR; It may or may not be bad for disk life, whereas it most certainly is affecting performance of the rest of your array. So probably best to split the VM off onto its own dedicated disk.

[bradlewa]

Thanks for the detailed response - much appreciated.  So I have the libvirt in a system share that is cache only, the iso is in a share that is set to cache "yes" and then the VM image is on the array...so a mix, but given the VM image is on the array, I would image it's the culprit as you suggest.  The downside to moving the VM image to a disk off the array is that you lose redundancy, correct? An alternative I could see is to assign the share that the VM image is stored in to 1 disk in the array, so that I could minimize the number of disks spun up all the time.  Downside to that?