I have two hard drives:
sda ST3500...blabla (doesn't matter) and sdb WD...blabla. I want to clone sda to sdb using dd.
I ran:
dd if=/dev/sda of=/dev/sdb bs=4096 conv=notrunc,noerror,sync.
The problem is that dd also clones the label of sda (ST3500...) onto sdb. While booting SUSE from sdb it searches for WD... and fails to boot. Is there a way to clone a whole drive with dd and maintaining the target drive label/model information?
The label is in the filesystem, not in the hard drive. It can be modified by filesystem tools such as tune2fs -L for ext2/3/4 filesystems. Simply modify the label after cloning.
you can change the label manually after cloning
I started a thread here for a debian system but I am sure it will also apply for SUSE
debian forum link
Related
'uname -a' on my machine gives:
Linux ct-lt-966 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux
Currently the filesystem of my USB is MS-DOS 'FAT32' which has a ~4.5 GB maximum size for individual files. I want to change this filesystem to something else, which does not have a limit. (I am trying to put a 35GB file onto a 64GB USB but I believe most USB filesystems do not limit the size of individual files).
I have not found it clear what choices of USB filesystem that I have. I tried to change the filesystem to 'NTFS', but I could not install or locate 'mkfs.ntfs' or even 'ntfsprogs'. (I also tried installing with 'pacman' and 'yum' but apparently 'pacman' requires an aarch architecture and I could not get access to 'yum-config-manager' in order to enable any repos).
So to conclude, with my minimal prowess I am just looking for any way to change the filesystem of my 64GB USB to anything which will accept a 35GB file from my machine.
Thanks
Edit 1: Just planning to use the USB on this Linux machine, not Windows.
If there's nothing on the stick you want, or it's safe to delete it then basically:
delete the current FAT32 partition from the stick
add a new partition, utilising the full size of the device
create an ext4 filesystem on the new partition
PLEASE BE CAREFUL WITH THIS PROCESS: selecting the wrong device can obliterate a disk you needed such as a $HOME or your root OS
All the following is from memory and untested: I don't have a USB stick available right now to test fully.
Start by plugging in the stick while tailing the syslog in a console and see where it gets mounted (hopefully it automounts which it should if it's a desktop based Linux you're running. Possibly not if it's a server)..
sudo tail -f /var/log/syslog
(it might be /var/log/messages depending on distro)
then plug the stick. syslog should show it being allocated a device and a mount point. A file manager window may open depending on your config if you are in a GUI. For example, you might see it being loaded on /dev/sdc1 and mounted at /media/<yourusername>/USBKEY or something.
Confirm by running lsblk and note the device for the key, i.e.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 167.7G 0 disk
├─sda1 8:1 0 69.9G 0 part /
└─sda2 8:2 0 97.9G 0 part /home
sdb 8:16 0 149.1G 0 disk
└─sdb1 8:17 0 149.1G 0 part /mnt/snapshots
sdc 8:32 0 931.5G 0 disk
└─sdc1 8:33 0 931.5G 0 part /storage
sdd 8:48 0 465.8G 0 disk
└─sdd1 8:49 0 465.8G 0 part /mnt/backup
sr0 11:0 1 1024M 0 rom
Unmount the stick (if it mounted) but leave it plugged in. Assuming again your device is at /dev/sdc1...
umount /dev/sdc1
Now run cfdisk in a terminal if you have it (friendlier) or fdisk if not, passing it the device related to your USB stick, without the partition number.
man cfdisk
sudo cfdisk /dev/sdc
This should show the current FAT32 partition. Delete it, then create a new partition of type 'Linux', following the defaults for start and end blocks which will be suggested in such a way as to fill the available space.
When done, select the option to Write the changes. Again, DOUBLE AND TRIPLE CHECK you have the right device or you will blow away your main disk probably.
Once the changes are written, you can create the ext4 file system;
sudo mkfs.ext4 /dev/sdc1
And after it completes, you should be able to re-plug your stick and find that it remounts, this time with a file system that can take your large files.
This isn't the only way to achieve this, but it's probably the least fiddly. For the sake of repetition, don't make a mistake with the device identifiers. If you're unsure, ask.
I have a server with the following disk structure:
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 219G 192G 17G 93% /
tmpfs 16G 0 16G 0% /lib/init/rw
udev 16G 124K 16G 1% /dev
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda2 508M 38M 446M 8% /boot
/dev/sdb1 2.7T 130G 2.3T 5% /media/3TB1
I am interested in making backup of the whole server on my local machine. When the time comes I want to be able to restore a new server from my local machine backup. What procedure do you recommend?
I tried rsync, but the indexing took extremely long so I aborted it. Than I used scp, and well, it is currently working. There is lots of symbolic links that weren't transferred to the local machine, and I worry I won't be able to restore it later on.
Since your sda isn't very large and a lot of it is used anyway, I'd create a complete backup of the block device. Your sdb, however, is very large and used only to a small part. Of that I'd create a file system backup.
Boot your server with a Ubuntu live CD and become root (sudo su -).
Attach your backup medium (I assume it's mounted as /mnt/backup/ in the following).
Create a block device backup of sda: cat /dev/sda > /mnt/backup/sda
Mount your sdb (I assume it's mounted as /media/3TB1/ in the following).
Create a file system backup of sdb: rsync -av /media/3TB1/ /mnt/backup/sdb/
For restoring the backup later:
Boot your server with a Ubuntu live CD and become root (sudo su -).
Attach your backup medium (I assume it's mounted as /mnt/backup/ in the following).
Restore the block device backup of sda: cat /mnt/backup/sda > /dev/sda
Mount your sdb (I assume it's mounted as /media/3TB1/ in the following).
Restore the file system backup of sdb: rsync -av /mnt/backup/sdb/ /media/3TB1/
There are more fancy ways of doing it for sure. But this routine worked for me lots of times.
A backup of that size should take a long time to copy over the internet in any case: rsync, cp , dd ..etc, the time taken to copy the file depends on your internet speed.
In my opinion, rsync is the way to go, but if you're not willing to wait that long for the download to complete (I wouldn't either) I highly suggest backing your disk up on another remote server, unless you don't plan on restoring it later since uploading would be a pain too (especially on ADSL).
You have a few options:
Ask your data center for disk redundancy.
A cheap and highly unrecommended solution is to backup your most important data on a file sharing web service, eg. Dropbox (As far as I remember they had a shell API for many tasks including uploading files, which can be used for automatic backups).
Wait for the download to finish.
Go with #Alfe's solution, which is pretty neat in my opinion.
I'm having problem to use this command under windows
dd if=*file* of=/dev/sdx bs=512 seek=2 conv=fsync
Using cygwin shell:
$ dd if=file of=/cygdrive/f bs=512 seek=2 conv=fsync
dd: failed to open ‘/cygdrive/f’: Is a directory
F: is the letter where my SD Card is mapped. What's the way to access it?
As you wrote dd if=file of=/dev/sdx
so you need to identify the device name sdx equivalent for your disk F:
On my system:
$ cat /proc/partitions
major minor #blocks name win-mounts
8 0 175825944 sda
8 1 175824896 sda1 C:\
8 16 1953514582 sdb
8 17 1953512448 sdb1 E:\
so /dev/sdb is the full USB hardisk and /dev/sdb1 is the first partition.
Pay attention to what you are doing. dd is a dangerous tool and can destroy your data/system
I never did find a good way to explicitly map a windows drive to a Cygwin drive but I did find a great alternate way to solve the problem/use dd on a windows machine.
dd is actually part of the package installed/shipped with Git for Windows. Once that is installed/unzipped if using the portable version you can find the binary in C:\Program Files\Git\usr\bin\dd.exe
The hardware mapping equivalent for if/of setting is written in the notation \.\DEVICENAME0 and can be found by running this PowerShell command (as-written also returns sector size)
Get-WmiObject Win32_diskdrive | select Caption,DeviceID,BytesPerSector,InterfaceType,Size
I make block device driver module and insert module on Ubuntu. And then I want to mount that module as file system using 'mkfs'command. But, mkfs command didn't work more with following message:
writing superblocks and filesystem accounting information
mkfs doesn't mount block devices. It creates filsystems on them. (I hope that there was nothing interesting on you device; mkfs has deleted the data on block device). To mount a block devices (or better to say to mount the filesystem that is on the blockdevice) you must use mount:
# mount /dev/sda1 /mnt
(presuming /dev/sda1 is the device you try to mount).
Don't forget to unmount the device when you need it no more:
# umount /mnt
We have a few linux based (Centos) virtual machines which are to be used as distributable virtual appliances. We want to be able to compress them as much as possible for distribution ( via tar.gz, zip, etc).
We've removed all unnecessary files (.log's, /tmp/*, /var/log/, etc) and have written /dev/zero to the free space on the disk.
Is it possible to write zeros via /dev/zero to the swap partitions and files? I know I would need to swapoff -a first. I'm worried about corrupting any internal structures.
Our vm uses both partition swap and file swap.
Also, are there any other strategies for reducing the size of a VM for distribution?
We need to support all of the hypervisor technologies (Xen, VMW, etc), so although the vendors tools maybe useful, I'm looking for strategies that are cross platform.
--- Thanks
You may want to write zeroes and then use mkswap to create an empty swap partition.
$ dd -if=/dev/zero of=/path/to/file bs=512 count=1
adjust the size that you want your files to be.
sudo swapoff -v /dev/sda2 <== The swap partition
sudo dd if=/dev/zero of=/dev/sda2 bs=512 status=progress
sudo mkswap /dev/sda2 UUID=46c1a133-bfdd-4695-a484-08fcf8286896 <== The original UUID of the swap partition