Preclear before initial start?

[ramblinreck47]

I'm planning on moving to unRAID next week. I've been waiting a long time to get everything ready for my move from Windows 10. I have several questions that would be awesome if they could get answered.

 

1. I have 2 x 8TB EMAZ drives that will be my initial drives in the array. Should I install the Preclear plugin before starting the array for the first time so I can do a Preclear before they go in? Or will just the formatting process be enough?

 

2. In addition to the 2 x 8TB drives, I have a 10TB EMAZ drive that I'll be using as my parity drive. Should I add the parity drive right away with the initial 8TB drives, Preclear it after the 8TB drives are installed, or just wait to add it until I move most of my data to the 8TB array from my external hard drive?

 

3. Should I add my 2 SSD's as cache drives right away when I do the 8TB drives?

 

Spaceinvader One's videos have been very helpful but the order in which to do certain things when first setting it up has me a little confused. Any help would be greatly appreciated!

[trurl]

There is a lot said about preclear still, but its original purpose no longer applies to recent versions of Unraid. Its only purpose now is to "burn-in" new disks to make sure they will not suffer from "infant mortality". If a disk is not new and its SMART attributes indicate it is in good health, no need to preclear. You can even use some other method to test and burn-in a new disk, including the diagnostic utilities provided by disk manufacturers as free downloads.

 

But note that it is very important that ALL disks be healthy. Every bit of parity PLUS ALL other disks must be reliably read in order to reliably reconstruct the data for a failed disk.

 

If you are doing an initial data load, it will be simpler (and probably faster) if you don't cache anything, and it will be faster if you don't have parity. Assuming you will be keeping the original data intact until you have your server loaded, there should be little risk running without parity initially. Also, parity is not a substitute for backups, so you should keep the original data intact even after you have parity until you have a good backup plan in place.

 

Even though I am recommending not caching until after the initial load, some other things will be simpler if you already have cache in place before you begin them. You shouldn't configure the Docker or VM services until you have cache installed or Unraid will have to put them on the array, which is not where you want them and you would have to do some work to get them on cache where they belong.

 

 

[ramblinreck47]

21 hours ago, trurl said:

There is a lot said about preclear still, but its original purpose no longer applies to recent versions of Unraid. Its only purpose now is to "burn-in" new disks to make sure they will not suffer from "infant mortality". If a disk is not new and its SMART attributes indicate it is in good health, no need to preclear. You can even use some other method to test and burn-in a new disk, including the diagnostic utilities provided by disk manufacturers as free downloads.

 

But note that it is very important that ALL disks be healthy. Every bit of parity PLUS ALL other disks must be reliably read in order to reliably reconstruct the data for a failed disk.

 

If you are doing an initial data load, it will be simpler (and probably faster) if you don't cache anything, and it will be faster if you don't have parity. Assuming you will be keeping the original data intact until you have your server loaded, there should be little risk running without parity initially. Also, parity is not a substitute for backups, so you should keep the original data intact even after you have parity until you have a good backup plan in place.

 

Even though I am recommending not caching until after the initial load, some other things will be simpler if you already have cache in place before you begin them. You shouldn't configure the Docker or VM services until you have cache installed or Unraid will have to put them on the array, which is not where you want them and you would have to do some work to get them on cache where they belong.

 

 

Awesome! Thanks for the quick response! I probably won't preclear the 8TB drives since they've been tested a couple of time with extended SMART tests and have been in constant use for about 6 months. The 3 other 10TB drives I have are brand new but have already passed extended SMART tests. I'll probably do a preclear on them if time allows just to be sure.

 

Looks like I'll add the cache drives when I get done with setting up the 8TB drives and wait to do docker containers till after they're added.

 

I can't wait to start setting everything up here later this week!