Reordering partitions to make room
So my current hard drives are:
# lsscsi [0:0:0:0] disk ATA Samsung SSD 860 1B6Q /dev/sda [4:0:0:0] disk ATA WDC WD4003FZEX-0 1A01 /dev/sdb [5:0:0:0] disk ATA WDC WD5000AAKS-0 3B01 /dev/sdc [5:0:1:0] disk ATA ST2000DM001-1CH1 CC29 /dev/sdd [10:0:0:0] disk WD Ext HDD 1021 2021 /dev/sde [11:0:0:0] disk WD Ext HDD 1021 2021 /dev/sdf
I had a lot of unused space on /dev/sdb, and thought I could rearrange the partitions and use it as an additional device in my (software) RAID.
I used Parted1, but GParted2 is also very nice. GParted can also scan my /dev/md127, which is a raid device.
Of course there's the general problem nowadays of looking what kind of MBR/GPT or whatever boot schema you use.
So:
Disk /dev/sdb: 3.64 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: WDC WD4003FZEX-0
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: D344E388-FA66-4B30-BA00-4D3B12A07B79
Disk model: WDC WD4003FZEX-0
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: D344E388-FA66-4B30-BA00-4D3B12A07B79
Device Start End Sectors Size Type /dev/sdb1 2048 4095 2048 1M BIOS boot /dev/sdb2 4096 1028095 1024000 500M Linux filesystem /dev/sdb3 1028096 5273437500 5272409405 2.5T Linux filesystem /dev/sdb4 5273438208 7420921855 2147483648 1T Linux filesystem
So it's a 4 TB hard drive, and it turns out that I only use /dev/sdb3. (The other partitions are from an old Linux install before I got a nice SDD and reinstalled Linux/Windows on that.)
So I could first rearrange it: resize /dev/sdb3 to 2T and move it to /dev/sdb1.
That worked fine using Parted. It just took some time to actually move all the data.
And then create a new /dev/sdb2 of 2T for my raid with gdisk3 (the GPT version of fdisk).
I had to look up the appropriate partition type in GPT4 for mdadm.
# gdisk /dev/sdb
GPT fdisk (gdisk) version 1.0.9
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): n
Partition number (2-128, default 2):
First sector (34-7814037134, default = 3907006464) or {+-}size{KMGTP}:
Last sector (3907006464-7814037134, default = 7814035455) or {+-}size{KMGTP}:
Current type is 8300 (Linux filesystem)
Hex code or GUID (L to show codes, Enter = 8300): fd00
Changed type of partition to 'Linux RAID'
Command (? for help): p
Disk /dev/sdb: 7814037168 sectors, 3.6 TiB
Model: WDC WD4003FZEX-0
Sector size (logical/physical): 512/4096 bytes
Disk identifier (GUID): D344E388-FA66-4B30-BA00-4D3B12A07B79
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 7814037134
Partitions will be aligned on 2048-sector boundaries
Total free space is 3693 sectors (1.8 MiB)
Number Start (sector) End (sector) Size Code Name
1 2048 3907006463 1.8 TiB 8300
2 3907006464 7814035455 1.8 TiB FD00 Linux RAID
Adding the device
Current raid setup:
# mdadm --assemble /dev/md127 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: /dev/md127 has been started with 3 drives.
# mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Wed Mar 6 22:16:05 2013
Raid Level : raid1
Array Size : 1953380160 (1862.89 GiB 2000.26 GB)
Used Dev Size : 1953380160 (1862.89 GiB 2000.26 GB)
Raid Devices : 3
Total Devices : 3
Persistence : Superblock is persistent
Update Time : Wed Aug 16 09:08:07 2023
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Consistency Policy : resync
Name : micemouse:0
UUID : ed4531c4:59c132b2:a6bfc3d1:6da3b928
Events : 7285
Number Major Minor RaidDevice State
4 8 65 0 active sync /dev/sde1
5 8 81 1 active sync /dev/sdf1
3 8 49 2 active sync /dev/sdd1
# cat /proc/mdstat
Personalities : [raid1]
md127 : active raid1 sde1[4] sdd1[3] sdf1[5]
1953380160 blocks super 1.2 [3/3] [UUU]
unused devices: <none>
Adding a device:
mdadm --add /dev/md127 /dev/sdb2
mdadm: added /dev/sdb2
md127 : active raid1 sdb2[6](S) sde1[4] sdd1[3] sdf1[5]
1953380160 blocks super 1.2 [3/3] [UUU]
unused devices: <none>
mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Wed Mar 6 22:16:05 2013
Raid Level : raid1
Array Size : 1953380160 (1862.89 GiB 2000.26 GB)
Used Dev Size : 1953380160 (1862.89 GiB 2000.26 GB)
Raid Devices : 3
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sat Aug 19 16:47:58 2023
State : clean
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Consistency Policy : resync
Name : micemouse:0
UUID : ed4531c4:59c132b2:a6bfc3d1:6da3b928
Events : 7286
Number Major Minor RaidDevice State
4 8 65 0 active sync /dev/sde1
5 8 81 1 active sync /dev/sdf1
3 8 49 2 active sync /dev/sdd1
6 8 18 - spare /dev/sdb2
root@localhost ~]# mdadm --grow /dev/md127 --raid-devices=4
raid_disks for /dev/md127 set to 4
# mdadm --detail /dev/md127
/dev/md127:
Version : 1.2
Creation Time : Wed Mar 6 22:16:05 2013
Raid Level : raid1
Array Size : 1953380160 (1862.89 GiB 2000.26 GB)
Used Dev Size : 1953380160 (1862.89 GiB 2000.26 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sat Aug 19 16:49:32 2023
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Consistency Policy : resync
Rebuild Status : 0% complete
Name : micemouse:0
UUID : ed4531c4:59c132b2:a6bfc3d1:6da3b928
Events : 7290
Number Major Minor RaidDevice State
4 8 65 0 active sync /dev/sde1
5 8 81 1 active sync /dev/sdf1
3 8 49 2 active sync /dev/sdd1
6 8 18 3 spare rebuilding /dev/sdb2
And now we wait.
# cat /proc/mdstat
Personalities : [raid1]
md127 : active raid1 sdb2[6] sde1[4] sdd1[3] sdf1[5]
1953380160 blocks super 1.2 [4/3] [UUU_]
[>....................] recovery = 0.1% (2956032/1953380160) finish=1156.0min speed=28118K/sec
unused devices: <none>
Ready in about 12 hours.
References
- [1] Parted User’s Manual
- https://www.gnu.org/software/parted/manual/parted.html
- [2] GParted is a free partition editor for graphically managing your disk partitions.
- https://gparted.org/
- [3] gdisk(8) - Linux man page
- https://linux.die.net/man/8/gdisk/
- [4] Raid Wiki Kernel Org - Partition Types
- https://raid.wiki.kernel.org/index.php/Partition_Types
- WP Guru - How to add a drive to software RAID with mdadm
- https://wpguru.co.uk/2021/01/expand-software-raid-mdadm/
