I'm setting up a unRAID box for my buddy tomorrow and have a quick question about the preclear process.  I'll be preclearing 4 x 3TB WD Red drives and saw this line in the Wiki:

 

"If you are pre-clearing multiple drives it is recommended you also use the optional "-r" "-w" and "-b" options. These set the size and number of blocks of data read and written to the disks during processing. Although not needed when clearing a single drive, If you do not use these options the preclear script may run out of memory when concurrently processing multiple large drives. Suggested values are

 

preclear_disk.sh -r 65536 -w 65536 -b 2000 -A /dev/sdX"

 

Is this a concern for 4 drives?  It's an i3 Box with 16GB of RAM if that matters.

 

We are also installing a SSD Cache drive.  Can I install my apps while the HDDs are preclearing?  I was going to assign the cache drive and then install NZBDrone and SABnzbd, but didn't know if that could be done without any shares being configured.  I'll be running the apps off the cache drive exclusively, but wasn't sure how that worked without having an array.

 

If you want to do 4 drives at the same time AND operate on other drives which exist on the bus, it's recommended to use the buffer assignments as provided.

 

This lets each job interleave a set of data for writes to the drives being cleared without overwhelming ram or the bus itself.

The data is only going to go so fast to the drives.

There's little reason to buffer so much in the cache if it's going to have to wait for the drives to carry out the instructions.

So just start each preclear using those block numbers and I'm alright to keep working on the cache drive while the preclears are running?

 

Are those still the recommended parameters?

 

Thanks!

So just start each preclear using those block numbers and I'm alright to keep working on the cache drive while the preclears are running?

 

Yes you can work on the cache drive. I'm not sure how much you can get done with all the data going to the bus.

 

Are those still the recommended parameters?

 

Thanks!

I don't have the answer to that. I would say try it and see.