Hack and / - Migrate to a New Hard Drive
What you do during this step will vary a bit, depending on how you set up your partitions. If you moved your partition layout around, you need to edit the /etc/fstab file on your new root partition so that it reflects the new drives you have set up.
Traditionally, this has been a simple step for me, because I try to order the partitions the same and generally don't have to touch fstab, but on this last migration, I had to add an extra step due to Ubuntu's use of UUIDs to reference partitions. A lot of modern distributions don't refer to partitions by their device name. Instead, a unique identifier called the UUID is assigned to each partition. If you see UUID=longstringofhex in your /etc/fstab, this means you.
Now, you have two choices here. The first choice is to change all these UUID lines to reference the actual device. This will work, and is less prone to typos that will make the system not boot, but you will lose the advantage of UUIDs. The other method is to reference the UUIDs for your new partitions and put them in place of the old UUIDs. You can find the list of disk-to-UUID mappings under /dev/disk/by-uuid:
greenfly@minimus:~$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 10 2008-04-06 16:00 ↪634719fd-a6da-4fee-8646-0d485d7681db -> ../../sda2 lrwxrwxrwx 1 root root 10 2008-04-06 16:00 ↪665d7008-fde9-4055-8af9-483697acb005 -> ../../sda1 lrwxrwxrwx 1 root root 10 2008-04-06 16:00 ↪cf3892fd-e3d8-446f-8552-4c633be9c382 -> ../../sda3
Of course, you always could choose a hybrid of the two approaches, and set the hard device names in the fstab for the first boot, and then once you have confirmed the system boots, you then can update fstab with UUIDs.
As with fstab, if you changed your partition layout, you need to update your GRUB configuration under /boot/grub/menu.lst (or on some systems, in /boot/grub/grub.conf) to reflect your changes. Also, GRUB can reference drives by UUID, so if you see references to UUID in the GRUB configuration file, be sure to update it to reflect the new values. Once the file has been updated, chroot into your new root partition's mountpoint and then run grub-install:
chroot /mnt/sdb1 /usr/sbin/grub-install --recheck /dev/sdb
Change /mnt/sdb1 and /dev/sdb to reflect your new mounted root partition and its disk device, respectively. If the chrooted grub-install doesn't work, you typically can use your rescue disk (or single user) grub-install with the --root-directory option:
/usr/sbin/grub-install --recheck --root-directory /mnt/sdb1 /dev/sdb
After I used my new system for some time, I noticed it wouldn't resume correctly from hibernation. It seemed like each time the swap partition would get corrupted. After some troubleshooting, I found that the root cause was a hard-coded resume device based on UUID that is put in the initial ramdisk for the machine. You may or may not run into this issue, depending on your Linux distribution, as each distribution manages its initrd differently. But, here is the fix for my Ubuntu system. I was able to find the offending reference to the old UUID in /etc/initramfs-tools/conf.d/resume. All I needed to do was update that file on the new drive to point to the new UUID for my swap partition, then run update-initramfs from the new system, and reboot.
Kyle Rankin is a Senior Systems Administrator in the San Francisco Bay Area and the author of a number of books, including Knoppix Hacks and Ubuntu Hacks for O'Reilly Media. He is currently the president of the North Bay Linux Users' Group.
Kyle Rankin is a VP of engineering operations at Final, Inc., the author of a number of books including DevOps Troubleshooting and The Official Ubuntu Server Book, and is a columnist for Linux Journal. Follow him @kylerankin.
Practical Task Scheduling Deployment
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.View Now!
|The Firebird Project's Firebird Relational Database||Jul 29, 2016|
|Stunnel Security for Oracle||Jul 28, 2016|
|SUSE LLC's SUSE Manager||Jul 21, 2016|
|My +1 Sword of Productivity||Jul 20, 2016|
|Non-Linux FOSS: Caffeine!||Jul 19, 2016|
|Murat Yener and Onur Dundar's Expert Android Studio (Wrox)||Jul 18, 2016|
- The Firebird Project's Firebird Relational Database
- Stunnel Security for Oracle
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- Managing Linux Using Puppet
- SUSE LLC's SUSE Manager
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Doing for User Space What We Did for Kernel Space
- Google's SwiftShader Released
- SuperTuxKart 0.9.2 Released
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide