Kernel Panic

[okoestner]

Hi,

my Raspberry suddenly talks to me like shown in https://onedrive.live.com/redir?resid=9 ... hoto%2cjpg. What can I do to get that machine back running without loosing my configuration?

Best regards,
Olaf

[DougieLawson]

You have a damaged filesystem on /dev/mmcblk0p2 (179,2). So you'll need to fsck that to get it back working.

Easiest way is boot a new SDCard and mount the broken card in a USB reader. You can then use sudo fsck -f -y /dev/sda2 to fix it. It's a good idea to keep a second bootable SDCard as a rescue system (or backup your live system on to it). I've got eight RPis, if I lose a filesystem I can use any one of the other RPis to rescue it. My USB reader cost £1 in the pound store.

[okoestner]

Hi Dougie,

thanks for your reply and sorry for my delayed answer. More or less your solution fixed my issue. There was some additional trouble with "invalid magic numbers in the superblock" which I fixed with the efsck tool.
My Pi is not back in a stable state.

One additional question: Do you have some good resources on how to backup my RasPi-Image from the SD card during up-time of my Pi?

Best regards,
Olaf

[DougieLawson]

I back my systems up to a 2TB NAS (which is mounted as /shared on all of my RPis).

sudo dd if=/dev/mmcblk0 of=/shared/Raspi/backups/`uname -n`.`date +'%F'`.img bs=40M &

[okoestner]

Thanks, that sound like being a great path for me either. Only thing I have to get managed is mounting my QNAP to the pi filesystem...

[DougieLawson]

If your QNAP NAS supports NFS then switch to using that. NFS is a billion times easier to use with Linux than Samba/CIFS.

[okoestner]

The QNAP is running a Linux on it. So I have to check how to create another partition with NFS.

[rpdom]

If the NAS is Linux, the filesystem on the partition is probably ext3 or ext4 - not that that matters much for the network file protocol being used.

Hopefully you should just be able to enable NFS access to the existing partition.

[DougieLawson]

Try using the showmount command with the IP address of your NAS.

pi@aplus ~ $ showmount -e 192.168.1.230
Export list for 192.168.1.230:
/i-data/xxxxxxxx/nfs/home 192.168.1.0/24
/i-data/xxxxxxxx/nfs/server 192.168.1.0/24
/i-data/xxxxxxxx/nfs/shared 192.168.1.0/24
pi@aplus ~ $

[okoestner]

My NAS has two drives which are configured as a RAID 1 mirror. The RAID volume is ext4 file system.
I don't want to change the RAID configuration so I have to go with connecting a ext4 to my raspberry. Any ideas on that?

[JimmyN]

One additional question: Do you have some good resources on how to backup my RasPi-Image from the SD card during up-time of my Pi?

Best regards,
Olaf

I don't know if QNAP has it already, or if it can be installed, but if so I'd use rsync to back up. The initial backup takes a while of course, but my daily backup of "/" every morning only takes about 20 seconds using rsync. If I've installed some more software then it will take a little longer as it has a lot of new files to copy.

[DougieLawson]

Look at the user control panel on your NAS. There's a very high (better than evens) shot that it WILL support NFS as a file sharing system. Most NAS boxes that are built on Linux have that feature.

You will NOT have to reconfigure any part of your (hidden, under the covers) NAS filesystem structure to activate that.

[okoestner]

Since there is already a lot of data on my NAS (QNAP TS-220) I assume building a new filesystem will cause me to format the drive. I don't want to do that.
What is the disadvantage going the way described in: http://geeks.noeit.com/mount-an-smb-net ... pberry-pi/

[DougieLawson]

The disadvantage are 1) the layers of code converting from Linux to CIFS on your NAS, CIFS to Linux on your RPi and 2) the complete lack of security. Security stops at the mount command.

It appears to be a control panel menu option to enable NFS.
http://docs.qnap.com/nas/4.0/en/index.h ... ac_nfs.htm

NO REFORMAT NEEDED!

[okoestner]

Wow... great!
I thought NFS to be another filesystem type.
NFS is now activated on my NAS. I will now have to check how to bind the NAS to my Pi.

[DougieLawson]

On your RPi run sudo apt-get install nfs-common rpcbind

Then run showmount --exports 192.168.nas.adr

That should give you something like
Export list for 192.168.nas.adr:
/i-data/xxxxxxxx/nfs/server 192.168.xxx.0/24
/i-data/xxxxxxxx/nfs/shared 192.168.xxx.0/24

You can then add those to your /etc/fstab

192.168.nas.adr:/i-data/xxxxxxxx/nfs/shared /shared nfs defaults,noatime,noauto,x-systemd.automount 0 0
192.168.nas.adr:/i-data/xxxxxxxx/nfs/server /server nfs defaults,noatime,noauto,x-systemd.automount 0 0

sudo /etc/init.d/rpcbind start
sudo mount /shared
sudo mount /server
gets them mounted without a reboot.

That "x-systemd.automount" stuff is needed to get Jessie with systemd to wait for the network to come up active before it tries to mount the shares. That means your NFS shares will be automagically mounted at reboot time.

On my NAS I even have /home mounted on a share.

[okoestner]

thanks a lot for your support!!

I tried to do it the way you wrote, but:

mount.nfs: access denied by server while mounting 192.168.0.100:/raspi

On my NAS I applied permissions for some users and also (for testing purposes) full access for guest account.
On my raspi I created the /mnt/nas with chmod 777.

[DougieLawson]

mount.nfs: access denied by server while mounting 192.168.0.100:/raspi

It's not filesystem permissions that need tweaking, it's NFS share permissions on your NAS. You have to open it to your whole LAN (or at least the static address for your RPi).

[okoestner]

Hmmm, have to figure out how to configure that in my QNAP. Up to know I did not find any configuration setting for that.

[DougieLawson]

Does this https://www.youtube.com/watch?v=kOkafwPzBXc help?

[okoestner]

Great, it works... I figured out where the configure the NFS settings. It is a bit different than in the video you linked, but nevertheless I found it and I was able to configure it correctly.

Now my next step is to build the proper backup command and apply a cron job to do this daily...

[DougieLawson]

I'm pleased it's worked for you, not bad considering I've not got a QNAP box, my NAS is a Zyxel.

For backup use rsync. rsync has the positive benefit that you only need to copy any of your data that's changed.