Preclear 4K alignment question; do I need -A?

[craigr]

I am just starting with unRAID as I migrate over from a FreeBSD ZFS system so I have a noob questions on preclear. 

 

I just bought 5x WD40EZRX and am currently running preclear on all of them.  When I started preclear I did not use -A.  I thought I had read that on the current version of preclear that if unRAID is set to use 4k alignment (MBR: 4K-aligned) in Disk Settings that preclear would automatically use 4K alignment (now I can't find where I read that).  Was this correct, or do I need to run preclear again with the -A argument?  My unRAID web GUI is set to MBR: 4K-aligned.

 

I also think I had read that there was a quick way to change a precleared disk to 4K alignment after the fact.  Is this true and if so what is the command?

 

Thanks,

craigr

[craigr]

I am using preclear 1.14 and unRAID 5.04.  From some other threads I have read it sounds like drives larger than 2.2 TB will automatically be 4K aligned.  It also seems that I could have used -A, but that it would have been silently ignored anyway.  Is this correct?

 

craigr

[BobPhoenix]

Correct.  I never use the switch myself on my 3 & 4TB drives.

[dirtysanchez]

Correct. The -A argument is silently ignored on all disks larger than 2.2TB because they are all GPT partitioned and 4k aligned by default.