mdadm serious does wrong partition changes
Dear Team,
I am creating raid partitions. First only sdd1, wanna add sdc1 later
on. But creating sdd1 does serious wrong partition changes. Because it
drops the partition tabel. And creates a new one.
First what do we have ...
# fdisk -l /dev/sdd
Disk /dev/sdd: 33.9 GiB, 36420075008 bytes, 71132959 sectors
Geometry: 255 heads, 63 sectors/track, 4427 cylinders
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: sun
Device Start End Sectors Size Id
Type Flags
/dev/sdd1 0 58589054 58589055 28G fd Linux raid autodetect
/dev/sdd2 58589055 71119754 12530700 6G 82 Linux swap u
/dev/sdd3 0 71119754 71119755 33.9G 5 Whole disk
Thats look okay for me. The same for lsblk.
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 136.7G 0 disk
├─sda1 8:1 0 957M 0 part /boot
├─sda2 8:2 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sda3 8:3 0 136.7G 0 part
sdb 8:16 0 136.7G 0 disk
├─sdb1 8:17 0 957M 0 part
├─sdb2 8:18 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sdb3 8:19 0 136.7G 0 part
sdc 8:32 0 33.9G 0 disk
├─sdc1 8:33 0 28G 0 part /home
├─sdc2 8:34 0 6G 0 part [SWAP]
└─sdc3 8:35 0 33.9G 0 part
sdd 8:48 0 33.9G 0 disk
├─sdd1 8:49 0 28G 0 part
├─sdd2 8:50 0 6G 0 part [SWAP]
└─sdd3 8:51 0 33.9G 0 part
sr0 11:0 1 1024M 0 rom
I wanna create raid on sdd1, so ...
# mdadm --create /dev/md2 --level=1 --raid-devices=2 missing /dev/sdd1
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md2 started.
Let see what we have done, it looks okay, true.
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 136.7G 0 disk
├─sda1 8:1 0 957M 0 part /boot
├─sda2 8:2 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sda3 8:3 0 136.7G 0 part
sdb 8:16 0 136.7G 0 disk
├─sdb1 8:17 0 957M 0 part
├─sdb2 8:18 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sdb3 8:19 0 136.7G 0 part
sdc 8:32 0 33.9G 0 disk
├─sdc1 8:33 0 28G 0 part /home
├─sdc2 8:34 0 6G 0 part [SWAP]
└─sdc3 8:35 0 33.9G 0 part
sdd 8:48 0 33.9G 0 disk
├─sdd1 8:49 0 28G 0 part
│ └─md2 9:2 0 27.9G 0 raid1
├─sdd2 8:50 0 6G 0 part [SWAP]
└─sdd3 8:51 0 33.9G 0 part
sr0 11:0 1 1024M 0 rom
So lets create a file system ...
# mkfs.ext4 /dev/md2
mke2fs 1.43.7 (16-Oct-2017)
Creating filesystem with 7319520 4k blocks and 1831424 inodes
Filesystem UUID: 17846385-0f08-4687-af85-ec4cfd7c0da2
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632,
2654208, 4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
But now, what goes on, after a reboot.
# reboot
Reconnecting ssh, you know. And let us see what we have done. So do a
lsblk again.
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 136.7G 0 disk
├─sda1 8:1 0 957M 0 part /boot
├─sda2 8:2 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sda3 8:3 0 136.7G 0 part
sdb 8:16 0 136.7G 0 disk
├─sdb1 8:17 0 957M 0 part
├─sdb2 8:18 0 135.8G 0 part
│ └─md0 9:0 0 135.7G 0 raid1 /
└─sdb3 8:19 0 136.7G 0 part
sdc 8:32 0 33.9G 0 disk
├─sdc1 8:33 0 28G 0 part /home
├─sdc2 8:34 0 6G 0 part [SWAP]
└─sdc3 8:35 0 33.9G 0 part
sdd 8:48 0 33.9G 0 disk
└─md2 9:2 0 27.9G 0 raid1
sr0 11:0 1 1024M 0 rom
So it has created the raid on sdd, instead of sdd1. And even
more serious, it drops my swap, and the Sun's sdd3 partition.
Thanks,
Frans van Berckel
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