First off: It is NOT your fault. It just shows that updates, without backups, are dangerous on ANY OS and no matter how often it worked before.
I had exactly the same problem today on Debian 9.
A whole ext3 RAID1 "vanished" after kernel was updated from:
linux-image-4.9.0-11-amd64 4.9.189-3+deb9u2
to
linux-image-4.9.0-12-amd64 4.9.210-1
list all installed kernels
dpkg --list | grep linux-image
ii linux-image-4.9.0-11-amd64 4.9.189-3+deb9u2 amd64 Linux 4.9 for 64-bit PCs
ii linux-image-4.9.0-12-amd64 4.9.210-1 amd64 Linux 4.9 for 64-bit PCs
rc linux-image-4.9.0-6-amd64 4.9.88-1+deb9u1 amd64 Linux 4.9 for 64-bit PCs
rc linux-image-4.9.0-8-amd64 4.9.144-3.1 amd64 Linux 4.9 for 64-bit PCs
ii linux-image-4.9.0-9-amd64 4.9.168-1+deb9u3 amd64 Linux 4.9 for 64-bit PCs
ii linux-image-amd64 4.9+80+deb9u10 amd64 Linux for 64-bit PCs (meta-package)
hostnamectl; # os used
Static hostname: storagepc
Icon name: computer-desktop
Chassis: desktop
Operating System: Debian GNU/Linux 9 (stretch)
Kernel: Linux 4.9.0-12-amd64
Architecture: x86-64
Those are the kind of "heart attack" moments X-D
Let's try to stay cool!
"solution": boot previous kernel ( in this case: linux-image-4.9.0-11-amd64 )
vim /etc/default/grub
GRUB_TIMEOUT=3 <- make sure a timeout larger than 0 is defined (or no time to select any options during boot)
# let grub2 do its stuff
update-grub
# is the same as:
uupdate-grub2
# reboot the system (if USB keyboard is not reacting during grub boot screen, try PS2 keyboard)
reboot
# when grub boot screen appears
After booting linux-image-4.9.0-11-amd64 kernel, can access ext3 RAID1 AGAIN!
Problem: grub won't remember that choice.
To make this permanent:
vim /etc/default/grub
# during boot:
## select in the first menu the second (0,1) entry
#### then select in the second menu select the 3rd entry (0,1,2)
GRUB_DEFAULT="1>2"
# make grub2 realize the changes
update-grub
... yes it is confusing I know X-D
this is what it was supposed to look like
Have two RAID1 defined.
# show status of raid
cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10]
md126 : active raid1 sdc1[1] sdb1[0]
3906886464 blocks super 1.2 [2/2] [UU]
bitmap: 0/30 pages [0KB], 65536KB chunk
md127 : active raid1 sde1[0] sdd1[2]
1953381376 blocks super 1.2 [2/2] [UU]
bitmap: 0/15 pages [0KB], 65536KB chunk
# show what is mounted
mount
/dev/md126 on /media/user/ext4RAID1 type ext4 (rw,relatime,errors=remount-ro,data=ordered)
/dev/md127 on /media/user/ext3RAID1 type ext3 (rw,relatime,data=ordered)
# show block devices
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
fd0 2:0 1 4K 0 disk
sda 8:0 0 238.5G 0 disk
├─sda1 8:1 0 230.8G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 7.7G 0 part [SWAP]
sdb 8:16 0 3.7T 0 disk
└─sdb1 8:17 0 3.7T 0 part
└─md126 9:126 0 3.7T 0 raid1 /media/user/ext4RAID1
sdc 8:32 0 3.7T 0 disk
└─sdc1 8:33 0 3.7T 0 part
└─md126 9:126 0 3.7T 0 raid1 /media/user/ext4RAID1
sdd 8:48 0 1.8T 0 disk
└─sdd1 8:49 0 1.8T 0 part
└─md127 9:127 0 1.8T 0 raid1 /media/user/ext3RAID1
sde 8:64 0 1.8T 0 disk
└─sde1 8:65 0 1.8T 0 part
└─md127 9:127 0 1.8T 0 raid1 /media/user/ext3RAID1
sr0 11:0 1 1024M 0 rom
# find defined raids
mdadm --examine --scan
ARRAY /dev/md/2 metadata=1.2 UUID=90642755:fa191325:0fe4ec59:2456c645 name=storagepc:2
ARRAY /dev/md/1 metadata=1.2 UUID=433fb7e1:9d7f3f17:bc5ee18b:0f4eeb52 name=storagepc:1
# show UUIDS
blkid /dev/sdb1
/dev/sdb1: UUID="90642755-fa19-1325-0fe4-ec592456c645" UUID_SUB="bee458e0-509a-c110-b577-8a1ddbe6bbb3" LABEL="storagepc:2" TYPE="linux_raid_member" PARTUUID="1fd02041-9dd2-4918-83a3-c8bafbab3bed"
blkid /dev/sdc1
/dev/sdc1: UUID="90642755-fa19-1325-0fe4-ec592456c645" UUID_SUB="7d5947f8-1ba0-0c7b-18a7-194ab4051a2c" LABEL="storagepc:2" TYPE="linux_raid_member" PARTUUID="5e4ea781-68e5-43f0-accf-26342aeb4daa"
userblkid /dev/sdd1
/dev/sdd1: UUID="433fb7e1-9d7f-3f17-bc5e-e18b0f4eeb52" UUID_SUB="bed17780-3817-27c9-6336-44d4aedfb857" LABEL="storagepc:1" TYPE="linux_raid_member" PARTUUID="f6aab6c2-01"
userblkid /dev/sde1
/dev/sde1: UUID="433fb7e1-9d7f-3f17-bc5e-e18b0f4eeb52" UUID_SUB="eb90b361-94d6-2f38-7727-d386097dce81" LABEL="storagepc:1" TYPE="linux_raid_member" PARTUUID="d2fd127f-01"
regular filesystem checks
Has nothing to do with the problem but defining this via tune2fs
has the advantage, that it will automatically be performed during boot.
tune2fs -C 2 -c 1 /dev/sda1; # check filesystem on every boot (for ext3 takes rather long X-D)
tune2fs -c 10 -i 30 /dev/sda1; # check sda1 every 10 mounts or after 30 days