GPT disks and parted / gdisk

Just notes.

# lsblk
NAME    MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda       8:0    0 931.5G  0 disk
├─sda1    8:1    0     1M  0 part
└─sda2    8:2    0    60G  0 part
  └─md0   9:0    0    60G  0 raid1 /
sdb       8:16   0 931.5G  0 disk
└─sdb1    8:17   0    60G  0 part
  └─md0   9:0    0    60G  0 raid1 /

# blkid /dev/sda
/dev/sda: PTUUID="e068d9e9-f2c3-4cfd-8927-17971d94bcae" PTTYPE="gpt"
# blkid /dev/sdb
/dev/sdb: PTUUID="7d3e7e2c-6b19-4d5c-a75b-8afec60cb1ec" PTTYPE="gpt"

# parted -a optimal /dev/sda set 3 swap on
Information: You may need to update /etc/fstab.

# parted -a optimal /dev/sda set 4 raid  on
Information: You may need to update /etc/fstab.

# parted -a optimal /dev/sda print
Model: ATA CT1000BX500SSD1 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name              Flags
 1      1049kB  2097kB  1049kB                                 bios_grub
 2      2097kB  64.4GB  64.4GB
 3      64.4GB  75.2GB  10.7GB               Linux filesystem  swap
 4      75.2GB  1000GB  925GB                Linux filesystem  raid

Create RAID 1

# mdadm --examine /dev/sda2
/dev/sda2:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : fe810c00:7f2f7925:faeaef92:d18128b5
           Name : ubuntu-server:0
  Creation Time : Thu Jan 13 00:09:33 2022
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 125761536 (59.97 GiB 64.39 GB)
     Array Size : 62880768 (59.97 GiB 64.39 GB)
    Data Offset : 67584 sectors
   Super Offset : 8 sectors
   Unused Space : before=67432 sectors, after=0 sectors
          State : clean
    Device UUID : 1deddf30:0d781840:e6ee3fdc:021fc5c9


# mdadm --create /dev/md1 --level=mirror --raid-devices=2 /dev/sda4 /dev/sdb4
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md1 started.


# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sdb4[1] sda4[0]
      903228096 blocks super 1.2 [2/2] [UU]
      [>....................]  resync =  0.2% (2007296/903228096) finish=74.8min speed=200729K/sec
      bitmap: 7/7 pages [28KB], 65536KB chunk

md0 : active raid1 sdb1[1] sda2[0]
      62880768 blocks super 1.2 [2/2] [UU]

unused devices: <none>
#

# watch mdadm --detail /dev/md1
Every 2.0s: mdadm --detail /dev/md1                                                                                                                                                     

/dev/md1:
           Version : 1.2
     Creation Time : Thu Jan 13 10:59:46 2022
        Raid Level : raid1
        Array Size : 903228096 (861.39 GiB 924.91 GB)
     Used Dev Size : 903228096 (861.39 GiB 924.91 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Thu Jan 13 11:59:57 2022
             State : clean, resyncing
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

     Resync Status : 39% complete

              Name : vm1:1  (local to host vm1)
              UUID : 5c82e79f:7afd7a4a:37f01db3:1c245334
            Events : 731

    Number   Major   Minor   RaidDevice State
       0       8        4        0      active sync   /dev/sda4
       1       8       20        1      active sync   /dev/sdb4