I've gotten my new unRAID server up and running.  Here are the specs:

 

 

• SUPERMICRO 12-bay Hot-Swap Chassis with SAS2-826EL1 Backplane
  
• SUPERMICRO X11SSM-F Motherboard
  
• Intel G4400 CPU
  
• Crucial 8GB (2 x 4GB) 2133Mhz DDR4 ECC Memory
  
• Dell H310 flashed the LSI P20 firmware
  
• Hitachi Deskstar NAS 4TB 7200 RPM x 2
  
• 2 x SUPERMICRO 500W 80+ Platinum Redundant PSUs
  

 

 

So far I've done the following:

 

• Flashed Dell H310 to LSI P20 firmware
  
• Ran Memtest for about 16 hours (15 full passes), no errors
  
• S.M.A.R.T short tests x 3 on both drives, S.M.A.R.T. long extended test on both drives, no errors
  
• And I'm now in the process of preclearing the disks
  

 

 

I'm currently still preclearing the two disks.  3 passes total and I'm currently 24 hours in and about 15% through the final phase (Post-read) of the first pass.  This seems to correlate pretty accurately with the "Preclear Times" section of the wiki which states these drives should take about 36 hours to preclear per pass.  By that math, the 3 passes should complete sometime mid day Wednesday...

 

My main issue is that I still have a lot to do.  Setting up Docker for Syncthing, Sonarr, CouchPotato and some others is most likely going to take me a couple days.

 

So on to my first question; can I start an array with only a cache disk?  My thinking originally was that I had no need for a cache disk.  I will never be writing anything to the array that isn't being directly downloaded to it.  In other words, my connection is going to be the bottleneck, not the write speeds of the disks.  I have a very fast connection (300Mbps/50Mbps), but even so the write speed of the array should be faster than that (about 30MB/sec).

 

My thinking now though is that I don't want Docker and my apps contained on the data/parity disks.  I can pick up a Samsung 850 Pro 128GB for $90 delivered today, and I'm wondering if I can start the array with only the cache drive and then start setting up Docker while my disks are preclearing (with no data or parity disks in the array).

 

 

Next question.  I have another Hitachi Deskstar NAS 4TB that I've been using for the last few months.  It's got data on it currently that I plan to transfer to the unRAID array and then I will preclear it and add it to the array.  My question is, do I need to run 3 preclear passes on it?  I understand the idea of running 3 passes is to stress the drives and simulate that first few weeks/months of use to weed out infant mortality.  Since I've been successfully using this drive for a few months, is that entirely necessary?  I currently plan on running 3 S.M.A.R.T. short tests and 1 long extended test, 1 preclear pass, then add it to the array.  Would it still be a good idea to run 3 passes?

 

 

I guess if I think of anything else I will post it here.  Thanks.

So on to my first question; can I start an array with only a cache disk?

 

Nope, you need at least one data disk assigned to start the array.

Well boo.  I'm going to be very bored for the next three days and then very busy the week after.

 

Thanks johnnie.black!

No, you don't need to run three pre-clear passes. You never do. It's just that some people advise it for brand new disks, while others don't. The choice is entirely personal. In this case it isn't a brand new disk and you're happy with it so just run one pre-clear pass and it will be ready to add to the array. Running the short SMART self-test three times in succession is pretty pointless but at least it's fairly quick.

No, you don't need to run three pre-clear passes. You never do. It's just that some people advise it for brand new disks, while others don't. The choice is entirely personal. In this case it isn't a brand new disk and you're happy with it so just run one pre-clear pass and it will be ready to add to the array. Running the short SMART self-test three times in succession is pretty pointless but at least it's fairly quick.

 

OK, that was pretty much how I understood it as well.  Thank you.