chroot which stands for change root allows you to virtually operate in another operating system even though you haven't booted it. It is commonly used to deploy new distros, applications and to fix a broken Linux/Unix install or prep a new system image without having to physically boot the drive or disk.
So in this example let's say we have a drive that has a Linux OS installed on /dev/sdb1 and we have mounted this partition on /mnt/sdb1
The key point is to edit the &quo........
Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install!
One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting
The normal way will not work here if your Centos was using UEFI. Newer systems use it by default.
The easiest way to check is to do an fdisk -l if your sy........
We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe! If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble.
Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
Iwill start by saying I think I know what caused this boot-time error on Linux Mint but should also apply to Debian and Ubuntu.
I changed my BIOS time to several hours in the past to match the current time, but this caused Linux to think there were incorrect filesystem times.
The problem is that it seems when you hit this I am not sure what is happening, it doesn't seem to be doing fsck and hangs without prompting the user.
What I have found is that........
In plain English this happens after you upgrade VBOX and it rebuilds kernel modules based on a newer kernel than you are running (eg. you upgraded your kernel but haven't booted into it).
It is too bad there is not a standard work around that would allow it to realize this and keep old kernel modules and use them if it detects your current kernel is older than the most recently build modules.
RTR3InitEx failed with rc=-1912 (rc=-1912)
In my case I could login with the initial install but I rsync'd everything over while preserving ownership and permissions to another RAID partition and booted from that.was fine before. The problem is that you are kicked out the second you login and the problem was SELINUX for some reason (perhaps it noticed something strange when it was moved to the new partition)
login: pam_unix(login:session): session opened for user root by LOGIN(uid=0)
login: ROOT LOG........
Iwas surprised to see that Linux Mint at the latest 17.2 version still has NO mdadm installer option, and worse the installer will not be able to create a proper booting environment even when you do install it.
How to setup mdadm in Linux mint LiveCD
apt-get install mdadm
# partition as you need and then create your mdadm devices
# create your SWAP md0
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /d........
Filesystem type unknown, partition type 0x83
grub> root (hd2,2)
Filesystem type is ext2fs, partition type 0x83
grub> setup (hd2)
Checking if "/boot/grub/stage1" exists... no
Checking if "/grub/stage1" exists... no
#weird thing about grub is that the drive you enter is considered hd0
For example when booted fu........
It really seems that 4.4.4 is not ready or stable for the i717 yet and this makes sense since it takes a lot of work/development and testing to get the factory stock ROMs working well. In the end I used the 4.1.2 based Blackstra BlackJelly because it was fast, stable and just works and feels great. The aftermarket support is great but many devs are focussed on adding features and customization that most of us don't want or need rather than getting things smooth and stable.........
-bash-3.1# shutdown -rn now
Connection to localhost closed by remote host.
Connection to localhost closed.
Sometimes I work with embedded systems/custom kernels without any of the fancy init scripts and other common Linux basics that most would expect. This means that often the "reboot" command (which uses an init script) will never work, not only that but it will hang the server and a manual power cycle or reboo........
I backed up everything in the /mnt/sd_card directory thinking that some dataloss could occur for some reason but purposely left my microSDHC unbacked up thinking that "it won't touch that since it's external" and Samsung's and other manufacturers website even say this (that it won't be affected and not to worry etc).
Apparently I was wrong, my microSD was "undetected" and asked to be formatted after the upgrade (there goes 3-months worth of family photos). No........
The best way I could figure out is to use another guest of some sort to do this, while assigning the disk that needs to be resized to the same guest.
So say we have /dev/xvda as the guests drive and we've booted it up.
We also have /dev/xvdb (this is going to be the image/disk to be resized).
In this case it's based on an ext3/4 image.
Run e2fsck on it to ensure there are no filesystem errors.
For years I've always built cheap systems believing that there is little difference in more expensive components when it comes to reliability and quality, I generally believe this still except for Power Supplies.
I've always bought cheap cases with nice sounding 350-550W stock/cheap/crap power supplies and haven't had any issues for the most part until recently.
One such case is an NGEAR case with a 550W Optimax power supply, I always read that these supplies don't produce the........
SIOCSIFFLAGS: Cannot allocate memory
Failed to bring up eth0
This is on a Centos 5.5 machine with OpenVZ kernel 2.6.18-238.12.1.el5.028stab091.1PAE, I updated 3 systems with the same hardware to the same kernel and for some reason the network didn't come back.
This only happened once the first time I booted into the new kernel and hasn't happened again but this is a serious issue for those running systems from remote locations such as a datacente........
Santrex never provided any working server, I believe it was just a dummy management Solus server because the server said it was booted but never connected to the console. I complained to them and eventually the support admitted the server was not working and to wait for 24 hours. I waited for 4-days, after which they sent an e-mail saying my service was being disabled for SPAM ...(when SolusVM shows 0kb of traffic). Th........
These are the only two I've encountered but here is the low-end and note my story is not at all unique.
In my case I was scammed out of money and did not receive any service at all from either company.
Santrex never provided any working server, I believe it was just a dummy management Solus server because the server said it was booted but never connected to the console. I complained to them and eventually the support adm........
I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks. It would only crash during the weekly RAID integrity check.
ThenI noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures.
You can imagine that a full blown RAID check........
I wanted to Import/Use a .vmdk hard disk image file from VMWare. Generally you can just "point" VirtualBox to it and use it and it will work but I found an exception.
One of my Centos 4.4 x64 images wouldn't boot. I had two copies, an older one and the newer one. The older one booted as normal (once I changed the VirtualBox driver to IDE from SATA). The newer one stopped at the "GRUB loading" message no matter what I tried.
As far as........
I successfully created a single RAID 1 partition which includes /boot inside it and my root directory through the Debian installer. It said GRUB installed successfully but when I try booting the OS it seems GRUB can't read anything.
When trying to boot from GRUB
GRUB Loading stage 1.5.
GRUB loading, please wait...
I get "Error 2" when trying to boot Debian. I also notice from a LiveCD that........
I installed 5.5 with a 300GB RAID 1 partition (boot is also on this partition). It booted up fine the first few times until after I used a Live CD and accessed the array, and it became named /dev/md127 for some reason.
Now whenI boot into CentOS I get a kernel panic and different errors, once I got "invalid superblock", even though the array is fine (it didn't happen again, probably because I was sure to dismount and stop the mdadm array properly).
Updated to Version 3.8 and can't loginSSHD accepts my password but then hangs at "Last login: Wed Sep 13 21:30:02 2006 from"
This occurred during a yum update after upgrading my release, installing the new kernel and rebooting.
I got kicked out of sshd after seeing the following during yum update:
telnet 100 % done 85/476
tux 100 % done 86/476
ntsysv 100 % done 87/476
rpmdb-redhat 94 % done 88/476........
Link Exchanges- Friendly AdviceI just wanted to make aware to the public who are paying to use Link Exchanges to get heavier traffic online and boosting their page rank in Google. Please be advised that this type of 'exchange' can very well get you booted off of Google and blacklisted by them! It's happened to many people and it's a very important tip. If you are on a Link Exchange, and have not been booted off yet; you MAY. Google is very smart and eventually they catch on. ;) Be ca........
100215 07:02:24 mysqld started
/usr/libexec/mysqld: Can't read dir of '/tmp/' (Errcode: 13)
/usr/libexec/mysqld: Can't create/write to file '/tmp/ibyP1qUC' (Errcode: 13)
100215 7:02:24 InnoDB: Error: unable to create temporary file; errno: 13
100215 7:02:24 [ERROR] Can't init databases
100215 7:02:24 [ERROR] Aborting
100215 7:02:24 [Note] /usr/libexec/mysqld: Shutdown complete
I wanted to disable the "Administrator" account for security purposes and Iread some "guide" on the internet that recommended that we run "C:WindowsSystem32sysprepsysprep.exe /generalize". I also clicked the option for "Generalize" and the computer rebooted and gave some OOBE error and restarted, and now I get the error above no matter what.
I read that some drivers such as ones from AVIRA AV can cause this because they're unsign........