I was trying to execute qemu while following the qemu/linaro tutorial,
https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Virtual_ARM_Linux_environment
I was executing the command,
sudo mount -o loop,offset=106496 -t auto vexpress.img /mnt/tmp
mount: you must specify the filesystem type
so i did fdisk on the img file and got the following,
Device Boot Start End Blocks Id System
vexpress.img1 * 63 106494 53216 e W95 FAT16 (LBA)
vexpress.img2 106496 6291455 3092480 83 Linux
The filesystem is Linux according to the fdisk command. But I get error,
sudo mount -o loop,offset=106496 -t Linux vexpress.img /mnt/tmp
mount: unknown filesystem type 'Linux'
Kindly help.
You correctly decide to mount the particular partition by specifying its offset but the offset parameter is in bytes and fdisk shows the offset in blocks (the block size is shown before the partition list --- usually 512). For the block size 512 the command would be:
sudo mount -o loop,offset=$((106496*512)) -t auto vexpress.img /mnt/tmp
If the automatic file system type detection does not still work there is another problem. Linux is not really a file system type. In the partition table it is a collective type used for multiple possible particular file systems. For mount you must specify the particular file system. In Linux you can list the supported ones by cat /proc/filesystems.
Related
I need to mount a USB drive to an embedded system, running Linux. The USB could be in FAT, NTFS or ExFAT format.
How can i handle this in code so that I pass proper type in mount command such as
mount -t vfat /dev/sda1 /mnt
So I have tried mount with:
mount -t vfat,ntfs /dev/sda1 /mnt
This command gives invalid argument, but it successfully mounts the USB if USB is in NTFS or VFAT format. However if i try to give
mount -t vfat,ntfs,exfat /dev/sda1 /mnt
The command fails.
Any pointers will be really helpful.
From the mount manual page:
If no -t option is given, or if the auto type is specified,
mount will try to guess the desired type. Mount uses the blkid
library for guessing the filesystem type...
Is libblkid available for your embedded system?
Try:
mount -t auto /dev/sda1 /mnt
or
mount /dev/sda1 /mnt
And as mentioned in the comments, make sure the kernel on your embedded system supports exfat.
I don't have much experience with Linux and mounting/unmounting things. I'm using Amazon AWS, have booting up EC2 with Ubuntu image, and have attached a new EBS volume to the EC2. From the dashboard, I can see that the volume is attached to :/dev/sda1.
Now, I see from this guide from Amazon that the path will likely be changed by the kernel. So it's most likely that my /dev/sda1 device will be mounted on, maybe, /dev/xvda1.
So I logged in using terminal. I do ls /dev/ and I indeed see xvda1 on there. But I also see xvda. Now I want to format the device. But I don't know if the unformatted device is attached to xvda1 or xvda. I cannot list the content of /dev/xvda1 and /dev/xvda (it says ls: cannot access /dev/xvda1/: Not a directory). I guess I have to format it first.
I tried to format using sudo mkfs.ext4 /dev/xvda1. It says: /dev/xvda1 is mounted; will not make a filesystem here!.
I tried to format using sudo mkfs.ext4 /dev/xvda. It says: /dev/xvda is apparently in use by the system; will not make a filesystem here!
How can I format the volume?
EDIT:
The result of lsblk command:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 8G 0 disk
`-xvda1 202:1 0 8G 0 part /
I then tried to use the command sudo mkfs -t ext4 /dev/xvda, but the same error message appears: /dev/xvda is apparently in use by the system; will not make a filesystem here!
When I tried to use the command mount /dev/xvda /webserver, error message appears: mount: /dev/xvda already mounted or /webserver busy. Some website indicate that this also probably because a corrupted or unformatted file system. So I guess I have to be able to format it first before able to mount it.
First of all you are trying to format /dev/xvda1, which is root device. Why ??
Second if you have added a new EBS, then follow below steps.
List Block Device's
This will give you list of block device attached to your EC2 which will look like
[ec2-user ~]$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvdf 202:80 0 100G 0 disk
xvda1 202:1 0 8G 0 disk /
Out of this xvda1 is the / (root) and xvdf is the one that you need to format and mount ( for the new EBS)
Format Device
sudo mkfs -t ext4 device_name # device_name is xvdf here
Create a Mount Point
sudo mkdir /mount_point
Mount the Volume
sudo mount device_name mount_point # here device_name is /dev/xvdf
Make an entry in /etc/fstab
device_name mount_point file_system_type fs_mntops fs_freq fs_passno
Execute
sudo mount -a
This will read your /etc/fstab file and if it's OK. it will mount the EBS to mount_point
I have a hard drive with ubuntu 14 installed. The whole disk is encrypted. My default users home directory is encrypted as well. Lately, after a system crash, I am presented with a busybox (initramfs) on startup. When I chose to start in recovery mode, I can grasp several error messages like " ... Failed to read block at offset xyz ...".
I searched and found this Q&A: Boot drops to a (initramfs) prompts/busybox
I booted from a CD and followed the instructions. However I am only able to do ...
sudo dumpe2fs /dev/sda1
... and then continue to check and repair superblocks on /dev/sda1 .
If I try ...
sudo dumpe2fs /dev/sda2
... i get the following error message:
dumpe2fs: Attempted to read block from filesystem resulted
in short read while trying to open /dev/sda2
Couldn't find valid filesystem superblock.
gparted shows the partitioning and file systems of the drive as follows:
partition file system size used unused flags
-------------------------------------------------------------
/dev/sda1 ext2 243M 210M 32M boot
/dev/sda2 extended 465G - - -
/dev/sda5!!crypt-luks 465G - - -
unallocated unallocated 1M - - -
The warning (!!) at sda5 says "Linux Unified Key Setup encryption is not yet supported".
If I try ...
sudo dumpe2fs /dev/sda5
... it returns this error message:
dumpe2fs: Bad magic number in super-block while trying to open /dev/sda5
Couldn't find valid filesystem superblock.
Mounting and rw-accessing sda1 works without error.
Any clues what is the cause and how i can repair, mount and decrypt the filesystem to boot normaly or at least to recover the data?
The given solution has missed some commands that you need to decrypt the file system and access it. Here's the full solution
Boot from Ubuntu USB
cryptsetup luksOpen /dev/rawdevice somename
sck /dev/mapper/somename
Get backup superblock:
sudo dumpe2fs /dev/mapper/ubuntu--vg-root | grep superblock
Fix:
sudo fsck -b 32768 /dev/mapper/ubuntu--vg-root -y
Verify:
mkdir /a
sudo mount /dev/mapper/ubuntu--vg-root /a
This worked for me:
Boot from Ubuntu USB
get backup superblock:
sudo dumpe2fs /dev/mapper/ubuntu--vg-root | grep superblock
fix:
sudo fsck -b 32768 /dev/mapper/ubuntu--vg-root -y
verify
mkdir /a
sudo mount /dev/mapper/ubuntu--vg-root /a
I used following links as source:
https://askubuntu.com/questions/137655/boot-drops-to-a-initramfs-prompts-busybox
https://serverfault.com/questions/375090/using-fsck-to-check-and-repair-luks-encrypted-disk
I'm trying to recover some data from a hard drive extracted from a broken laptop, and I'm having problems mounting the disk to my current system (Linux Mint). The hard disk I'm recovering from ran Debian. Simply, I'm confused as to how I can mount the hard drive to access the files, however it's not as simple as any other mount I've done. The following details struggles and information I've encountered.
I get the following outputs when trying to mount the hard drive with different file-system tags. I should add that the file-system type isn't automatically detected when using auto, and "sdb" is definitely the correct address for the disk (taken it from dmesg).
$ mount /dev/sdb /mnt/usb -t ntfs
NTFS signature is missing.
Failed to mount '/dev/sdb': Invalid argument
The device '/dev/sdb' doesn't seem to have a valid NTFS.
Maybe the wrong device is used? Or the whole disk instead of a
partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?
The following returns the same message when all other common file-system tags are used:
$ sudo mount /dev/sdb usb -t ext2
mount: wrong fs type, bad option, bad superblock on /dev/sdb,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
The results from these commands led me to believe that there was an issue with the hard disk and it's partitions, however fdisk proved that it's partition's do seem to be valid and correct:
$ sudo fdisk /dev/sdb -l
Disk /dev/sdb: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0002da94
Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 475920383 237959168 83 Linux
/dev/sdb2 475922430 488396799 6237185 5 Extended
/dev/sdb5 475922432 488396799 6237184 82 Linux swap / Solaris
I then decided to try verify the file-system type of the hard drive, which seems to be "devtmpfs", which I got from the following command using df:
$ df /dev/sdb -T
Filesystem Type 1K-blocks Used Available Use% Mounted on
udev devtmpfs 1014764 4 1014760 1% /dev
And so finally, I mount the hard drive using -t devtmpfs, which is successful in mounting however I'm left with a confusing file system very unlike from what I would expect from what was a standard debian set up.
It contains file folders such as "block","bus","char","disk","dri","mapper"... and files like "sda1","sdb","sdb1","tty","vcs".
I'm totally stumped as to how I should progress, and I'm pretty convinced the hard disk isn't broken and that I'm just mounting it incorrectly. How can I successfully mount the disk so I can access my files? Any help would be greatly appreciated.
Ok, you are trying to mount the entire disk instead of individual partitions, which is why you are getting the error. In short the command you need is:
mount /dev/sdb1 /mnt/usb
The file /dev/sdb references the entire disk as a block file. This includes the partition table at the start, which is why it can't find a filesystem. The file /dev/sdb1 references the first partition, which is where your filesystem will be. From the looks of your fdisk output, this is not an ntfs partition since this is a Windows filesystem and the partition is marked as Linux (most likely you will have ext4 unless you specifically set up something different).
To add a quick explanation of devtmpfs, this is a special filesystem which contains these block files which are specified by udev. You can google both for more information, but by now I'm sure you now know its not what you are looking for.
How to determine the type of file system on an SD Card (this card is not yet mounted. I need to determine the file system type so that i can mount the SDCard through a program according to the file system type)
Or from the terminal. For example "mount -t ext3 /dev/sdc1 /mnt"
You might do a file -s /dev/sdc1 and it could recognize the filesystem data.
And you might do mount -t auto /dev/sdc1 /mnt to have mount recognize it.