I have a bootable IDE hard drive which has Linux on it(with GRUB bootloader).
I need to extract files inside this hard drive, but the problem is the booting fails
because of some reason... super-block or boot sector must be corrupted. (the hard drive uses EXT3 partition)
So I am trying to mount my corrupted hard drive into another system and extract data from there. however, if I mount my corrupted hard drive, the fdisk -l tells me that "Disk /dev/sdb doesn't contain a valid partition table"
In the worst case, I want to recover even some partial data off from this disk. what would be the best way to do this?? Thank you in advance.
You can run any linux live CD/DVD and then you can be able to get required files
If you want to fix boot sector then refer this link
Related
I'm a veryyyy beginner please sorry for this question. I'm trying to understand file system and mounting.my question is to mount a hard drive did linux need to know already the file system?.I will make an example:if I removed vfat from linux so there is no file system like that and I want to mount a hard drive that vfat is he's file system can linux mount it.
I'm learning file system and I'm soo confused if u have some good materials please share it with me
You normally mount not drives but filesystems. In general a drive is partitioned and each partition is formatted with a specific file system.
To answer your question, in general you don't need to specify what type of file system you are mounting. Linux can detect the type from the file system metadata, except where there is no metadata and you need to use the "-t" parameter to say explicitly what type of filesystem you are mounting.
For vfat this call should be sufficient, if your VFAT filesystem is on /dev/sda1:
mount /dev/sda1 /my/mount/point
If I have a device mounted in RHEL, how do I add another device to it and make it a raid0 config?
I know how to mount two new devices in a raid0 config, but how do I do it with one device that is already in use and has data on it?
Depends on the details; is it an lvm volume? Then add the new device to the volume group and extend the logical volume. Is it a file system like ZFS? Then add the device to the pool. Otherwise, you need to backup the mounted drive, unmount and create a raid0 volume.
Save you some headaches and clone the drive with a disk imaging software like Clonezilla (http://clonezilla.org/).
Once you have your drived cloned as a disk image, set up RAID0 and recover your clone to the newly created RAID, telling Clonezilla to expand to the total size of the disk.
This way, even if something goes wrong, you can always undo the whole process and just recover your clone into the original single disk as if nothing happened.
Hope it helps,
Regards
I don't think it's possible. You can't have a mounted drive and convert it into a RAID array along with another drive. You will surely have to unmount it first. More realistically, you'll probably have to reformat the drive before adding it to a RAID array. Understand that the RAID is being managed at a lower level than the OS. The OS sees the RAID array as one partition. The OS has no ability to manage or add drives to an existing RAID array.
After running BitBake on several different recipe files, BitBake generates a file of type '.hddimg'. I haven't been able to find a clear explanation on what this file is used for, the closest that I have found is some speculation on the mailing list here. The author Paul states that:
the image isn't an image of a regular bootable system drive, but is a "live
image" of a smaller system that can either boot the real system from a
virtualized file system in RAM whose image is read from a single file in the
first level, or it can install the real system to a different drive.
The 'bootimg.bbclass' is what generates the .hddimg, and in the opening comments it is written that:
A .hddimg file [is] an msdos filesystem containing syslinux, a kernel, an initrd and a rootfs image. These can be written to harddisks directly and also booted on USB flash disks (write them there with dd).
Which appears to corroborate with what Paul wrote, but still leaves a lot of ambiguity on how to go about booting from this file (at least to a greenhorn like me).
Well, the doc says "write them there with dd". So:
dd if=/path/to/your/hddimg of=/path/to/raw/usb/device
so, if you have the file as my.hddimg and the usb flash disk appears as /dev/sdg
dd if=/home/karobar/my.hddimg of=/dev/sdg
As it's name implies, it's an image, so needs to be written as such. The actual file system is inside of the rootfs file, which is similarly an image!
Once you have that on the usb stick, the usb stick itself should be bootable. Depending on what you're trying to do this may not be the easiest kind of output from bitbake to work with.
I want to add a new ext3 partition by editing existed scripts or adding new scripts in initramfs in boot folder of installed CentOs. and then by replacing the new initramfs image to other installed centos and just by a reboot, a new partition ( and its file system) appear in new CentOs.
my problem is that , i don't know which script in initramfs i should change, or which new shell script i should write there? with which command and how? for example should i use fdisk command? i try but not success..
any help will be appreciated.
I'm gonna go on a guess here.
If I understand what you want to do correctly, what you want to do is to make another ext3 partition visible in CentOS.
If so, you want to make sure that the partition exists. Maybe you have a disk called /dev/sda it might have 2 partitions:
sda1 ext3 mounted at /boot
and sda2 ext3 mounted at /
To view this use sudo blkid, fdisk-l or similar. These partitions are loaded at boot from the list found in /etc/fstab.
Say you still have space left on the disk. Use fdisk/gparted to create a new ext3 partition sda3. Add a line for that disk in /etc/fstab.
Now it should be accessible after a reboot or after sudo mount -a.
I might have completely misunderstood your question.
Edit #1
I think I understand what you want to do now, and you probably want to edit the /etc/fstab within the initramfs. I have never tried doing this and I don't know if it would work, but it should. In any event, unless you really need to mount the partitions in initramfs, use the above to mount it in fstab.
Extracting the contents of and repacking an edited initramfs is rather complex, but here are some links explaining how to extract and repack, they are for gentoo but there should be no difference:
http://forums.gentoo.org/viewtopic-t-429263-highlight-initramfs.html
http://forums.gentoo.org/viewtopic-t-383198-highlight-cpio.html
http://forums.gentoo.org/viewtopic-t-388539-highlight-.html
If you read those threads you should be able to use a script or C program to extract the contents of the initramfs, change the contents of /etc/fstab within initrams, and extract it back together. If you need to do this for different computers they will need to need the same contents in initramfs, or you need to do this for each computer setup.
Right, so I've got a Ramdisk image on a mounted device at, say, /mnt/sda1/Ramdisk.img . I want to copy the raw data directly to a ramdisk device at /dev/ram0, in such a way that there will be no need to use mke2fs: I could mount the image and device and find that both are identical.
Ideally this would use only linux commands.
My ideas so far: Mounting the image on a loopback and using basic IO to put the data from one device into the other. I could probably do this with C.
Also, somehow finding the physical address of the ramdisk device and using linux or C commands to put the file directly into the memory.
Thanks in advance.
P.S: I know that the kernel somehow flags memory which was used for ramdisks so the system does not reclaim it. Anyone know where these flags are?
Any kind of copy command is going to require a partition and filesystem at the destination. However, dd can work at the disk or partition level, by just specifying the disk (eg /dev/sda) or partition (eg (dev/sda1) level. So in theory, you could do
dd if=ramdisk_image_file of=/dev/ram0