Should I disable timer on new drives as well? Thanks
As I said in an earlier posting, 300 seconds (5 minutes) is a very reasonable value. I would only recommend disabling the timer if you were in a high use environment like a small office where people are going to constantly be accessing data or in a home environment where you are running applications (plugins or system data set on the drives) which access data very frequently but just outside the 5 minute window.
To address a high use environment first... If you are in a high use environment if the heads are parked it will cause a delay (it's minor but it does irritate people) in retrieving the data so those types of system would typically want to leave the heads on the platters.
All WD Red drives are rated for 600,000 head loading cycles now, keep that in mind. This means 547 loads per day or once every 2.63 minutes. That means that if you set your timer for 5 minutes (288 counts a day maximum), you will never hit the maximum value under your 3 year warranty. Setting it up to 5 minutes means you would hit the maximum limit in just 5.4 years of operation.
We could simply state that 300 second value was good for any situation however it isn't and I wouldn't be happy if my load cycle counts were going up over 80 counts a day (that is a personal value, everyone would have their own personal cut-off point). I wouldn't loose any sleep over it either but I would change it myself to disable the head loading.
So to evaluate how your FreeNAS system is doing with respect to the head load cycle count, set them all up for 300 seconds and after you have your new FreeNAS system up and running record at the head loading count on all your drives (if they are all set to 300 seconds, you only need to record a single drive value but if you record all of them, you will know if all are actually set to 300 seconds and one didn't get missed), wait a few weeks and record it again. Now comes a judgement call on your part, can you live with the value? Do not forget to subtract any time you cycled power or rebooted the computer or if you are trying to sleep the drives as those will drive up the count. You might have 0 to 10 count which means your drives are almost constantly being accessed or a low value can also mean that you rarely use your NAS so you need to know what your usage is and put things into perspective. If you have a high value of 3800 or more then you are accessing data frequently just outside the 5 minute park period and immediately reloading the heads. Personally I'd disable the head loading if I had a high count like that, but it does still fall into the warranty period so you can technically leave it that way, but I wouldn't.
The reason I say to evaluate over a 2 week period is because of your specific use, I don't know it. You could evaluate over a much shorter period of say 2 days if you want (I would but I know what I'm looking at) and see what you come up with.
No problem with a LCC of 4000 after one year, even if the drive would last 50 years the LCC would still be ok :)
That is the value in the old NAS unit, not a FreeNAS unit so it's not the same thing.
Head parking may actually be good thing when it happens appropriately.
I 100% agree with this statement and that is why I try to push everyone to use 300 seconds initially. It's when the heads are constantly unloading and then seconds later load and the end user must figure that out. And to go along with this comment, do not disable the timers if you do not have an UPS unit which is controlled by your FreeNAS unit. If you cannot properly shutdown your system which will park the heads nicely then you are depending on the drive mechanics to do it. That's not a major issue these days however I would never operate that way under normal circumstances. Also you need to have the UPS to prevent data corruption.
@wrath I'd like to see what you come up with once you have your FreeNAS established.
