On 2017-07-03 08:10, David C. Rankin wrote:
See:
https://wiki.archlinux.org/index.php/RAID
Create the Partition Table (GPT)
It is highly recommended to pre-partition the disks to be used in the array. Since most RAID users are selecting HDDs >2 TB, GPT partition tables are required and recommended. Disks are easily partitioned using gptfdisk.
After created, the partition type should be assigned hex code FD00. If a larger disk array is employed, consider assigning disk labels or partition labels to make it easier to identify an individual disk later. Creating partitions that are of the same size on each of the devices is preferred. A good tip is to leave approx 100 MB at the end of the device when partitioning. See below for rationale.
Huh? Let's see: «When replacing a failed disk of a RAID, the new disk has to be exactly the same size as the failed disk or bigger — otherwise the array recreation process will not work. Even hard drives of the same manufacturer and model can have small size differences. By leaving a little space at the end of the disk unallocated one can compensate for the size differences between drives, which makes choosing a replacement drive model easier. Therefore, it is good practice to leave about 100 MB of unallocated space at the end of the disk.» Curious! It also says: «Note: It is also possible to create a RAID directly on the raw disks (without partitions), but not recommended because it can cause problems when swapping a failed disk.» -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" at Telcontar)