Eu tinha um array RAID0 de 1 disco que criei com o objetivo de adicionar mais discos a ele eventualmente, que estava funcionando normalmente. Eu criei com (aproximadamente):
$ mdadm --create /dev/md0 --raid-devices=1 --level=0 /dev/sdb -f
Então eu adicionei outro disco a ele com:
$ mdadm --grow /dev/md0 --add /dev/sdc --raid-devices=2
e, conforme o manual, mdadmconverteu o array para RAID4 e começou a sincronizar novamente. O manual diz que a matriz será convertida novamente para RAID0 posteriormente. No entanto, /etc/mdstatdiz que levará de 2 a 3 dias para uma ressincronização completa, e estou me perguntando se é possível parar o array, matar o superbloco em /dev/sdce fazer algo como:
$ mdadm --create --assume-clean --verbose /dev/md0 --chunk=512 \
--level=0 --raid-devices=2 /dev/sdb /dev/sdc
em vez de esperar pela ressincronização inútil do RAID4?
No momento, o estado do array é:
$ mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : XXXXXXXXXXXXXXXX
Raid Level : raid4
Array Size : 11718754304 (11175.88 GiB 12000.00 GB)
Used Dev Size : 11718754304 (11175.88 GiB 12000.00 GB)
Raid Devices : 3
Total Devices : 2
Update Time : XXXXXXXXXXXXXXXX
State : clean, FAILED, reshaping
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1
Chunk Size : 512K
sistency Policy : resync
Reshape Status : 2% complete
Delta Devices : 1, (2->3)
...
[root@centos7 ~]# mdadm --stop /dev/md0
[root@centos7 ~]# mdadm -E /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x44
Array UUID : 5978222a:8f2c320c:c7059108:c3d6dc41
Name : centos7:0 (local to host centos7)
Creation Time : Sat Apr 28 05:15:00 2018
Raid Level : raid4
Raid Devices : 3
Avail Dev Size : 23437508608 (11175.88 GiB 12000.00 GB)
Array Size : 23437508608 (22351.75 GiB 24000.01 GB)
Data Offset : 262144 sectors
New Offset : 260096 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 9a75cd7e:bb469dab:2e0db890:69a68f54
Reshape pos'n : 620094464 (591.37 GiB 634.98 GB)
Delta Devices : 1 (2->3)
Update Time : Wed Aug 1 06:12:00 2018
Bad Block Log : 512 entries available at offset 8 sectors
Checksum : d239a780 - correct
Events : 608
Chunk Size : 512K
Device Role : Active device 0
Array State : AA. ('A' == active, '.' == missing, 'R' == replacing)
[root@centos7 ~]# mdadm -E /dev/sdc
/dev/sdc:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x46
Array UUID : 5978222a:8f2c320c:c7059108:c3d6dc41
Name : centos7:0 (local to host centos7)
Creation Time : Sat Apr 28 05:15:00 2018
Raid Level : raid4
Raid Devices : 3
Avail Dev Size : 23437508608 (11175.88 GiB 12000.00 GB)
Array Size : 23437508608 (22351.75 GiB 24000.01 GB)
Data Offset : 262144 sectors
New Offset : 260096 sectors
Super Offset : 8 sectors
Recovery Offset : 620094464 sectors
State : clean
Device UUID : ce6e93f9:729557dc:a1afc6a4:39b954f9
Reshape pos'n : 620094464 (591.37 GiB 634.98 GB)
Delta Devices : 1 (2->3)
Update Time : Wed Aug 1 06:12:00 2018
Bad Block Log : 512 entries available at offset 264 sectors
Checksum : 5b8389b4 - correct
Events : 608
Chunk Size : 512K
Device Role : Active device 1
Array State : AA. ('A' == active, '.' == missing, 'R' == replacing)