Tuesday, 22 May 2012

New PC Install Notes


This post documents how I installed Linux and Windows side-by-side in a dual boot configuration.  This isn't something particularly difficult to do but I wanted to note down what I did so I remember in years to come.  Also, my new PC build contains some very up-to-date hardware (such as UEFI and an SSD drive) and with the combination of the many changes and updates to Fedora 17 (F17) and Windows 7 SP1 (Win7) it made the installation a first of a kind for me in quite a few different ways.

This post may well be updated in the future if I do further installation tweaks and optimisations to the system.  There's also clearly a lot more you can do in terms of system set up than I've written here, installation of drivers in Win7 very much being one of those.  This is simply intended as an installation and base optimisation guide.

Create USB Boot Sticks

Due to a fault with the DVD writer I ordered, it's on its way back to the retailer for replacement.  Not one to let this stop an installation going ahead I wrote install images for F17 and Win7 onto USB stick.

F17 is still in beta with the full release delayed until 29th May at the time of writing.  I tried writing and booting from the KDE Spin Beta Live image but it stopped with a kernel panic during the boot process after the grub screen.  I found using a later copy of the boot.iso (which is the same as a netinst.iso) from the distribution nightly builds solved the problem so clearly whatever the bug is on the beta image it's already been solved.

Creating a USB stick for Fedora is pretty easy these days, no messing around on the command line, I decided to use the liveusb-creator utility.  It fires up a GUI from which you basically just select the iso image you want to write and the USB device to write to, then hit "go" and it does the magic for you.

For me, writing the Windows stick was a little more complicated as it requires a Windows system to run the stick writing utility with the somewhat strange and long winded name of the Windows 7 USB/DVD Download Tool.  Fortunately, I had a Windows 7 VM laying around so I used that and writing the image to USB stick was similarly easy as it was for Fedora.  Simply choose the image file to write, the target device to write it on, then hit "go" and it does the magic for you.

Install Fedora 17

Once I worked around the kernel panic bug I mentioned above and booted with a later F17 image, the installation process was a fairly familiar affair.

With the new PC being a UEFI box there was no need to add the GPT partition when partitioning the SSD. I simply created one large root partition and a 4GB swap partition, leaving half the disk unallocated for the Win7 install later.

Since I didn't boot from the KDE spin image, I swapped out the default Gnome desktop (I've tried hard for a long time to Like Gnome 3 but I just don't so I'm moving back to KDE) and did a lot of package selection using the installer to save me messing around later but also to optimise the amount of data downloaded since I would be installing over my ADSL connection.

Once tip when installing Windows after Linux these days is to ensure the os-prober RPM gets installed.  This was done by default for me.  This package allows grub to detect the presence of other operating systems and add boot entries for them in the grub menu.  It'll come in very handy later on...!

SSD Optimisations for Linux

Even with a distribution as current as Fedora 17, the settings chosen for SSD usage are really rather sub-standard.  There are a lot of handy tips and guides out there for which settings you should change or add to the system to enhance both the performance and longevity of your SSD.  I decided to go with the rather comprehensive information provided for the Arch Linux distribution as they have a great wiki page on SSD optimisation.


Update /etc/fstab

I've only got one SSD in my system at the moment, I've removed all my old hard disks with no intention to use them right now as all my data is stored on my NAS.

Add the "noatime" and "discard" options to SSD partitions.  The discard option is the really super-important one as it turns on TRIM.

Mount /tmp as tmpfs by adding a line similar to the following:
  tmpfs /tmp tmpfs nodev,nosuid,size=75% 0 0

Doing this allows the system to write temporary files to RAM instead of the SSD.  This will improve performance (RAM is faster than SSD) and reduce writes to the SSD (improving the life of the SSD).  I've added an option to increase the allowable size of the tmpfs file system to 75% of RAM from the default of 50%.  This means I can run compilations or other intensive tasks in RAM without ruining the SSD and get the performance benefits too.  With 16GB main RAM, this will allocate up to 12GB for my /tmp directory.  In normal usage I wouldn't expect to use anywhere near this but it's nice to have it there for when I'm not running too many apps but doing something else such as compiling RPMs.

Change the Scheduler

The recommendation for an SSD is to move away from the default cfq IO scheduler and switch over to the noop scheduler.  This can be done in a variety of ways that are documented in the Arch Linux wiki page I've linked above.  Since I've only got 1 disk in my machine and it's an SSD I changed the scheduler option using grub.

For Fedora 17 this consisted of an edit to the /etc/default/grub file and adding elevator=noop to the existing GRUB_CMDLINE_LINUX stanza.  Then rebuilding the grub configuration with the command:
grub2-mkconfig > /boot/grub2/grub.cfg

Optimise Kernel Parameters

With 16GB main RAM I'm not expecting to do much in the way of swapping.  However, I did add a couple of lines to /etc/sysctl.conf to make the system less likely to do so:
  # make the system less likely to swap
  vm.swapiness=1
  vm.vfs_cache_pressure=50


Install Windows 7

Similarly to the F17 install, the Win7 install proceeded with little in the way of drama.  I did select the advanced install option when given the chance but that was just to ensure Win7 installed into the free space I had left on the SSD rather than rudely splat my shiny new F17 installation.

And yes, for those of you wondering why I'm installing Win7 at all, especially dual boot rather than in a VM, it's simply for those times when only Windows will do... so gaming mostly I should think.

There's not much else to do with Windows after installation.  Unlike current Linux distributions it's said to  detect the presence of an SSD drive and apply the appropriate optimisations automatically.  Whether this is entirely true or not I suspect I'll never be any the wiser to.

Update the Boot Loader

So Win7 didn't kill off my F17 installation which is always a bonus, but it does assume divine rights over the entire system so writes its boot loader all over the existing grub installation allowing you only to boot windows with no menu options for anything else - not ideal.  Now I need to re-install grub which I've always found easiest to do by booting a rescue Linux CD and using a chroot to the installed OS.  This has changed slightly with the inclusion of grub 2 so here's what I did.

Boot the F17 USB stick once again but this time choose the "troubleshooting" boot option and select to boot the "rescue environment".  Red Hat based systems have always done a great job of rescue environments so you'll boot into a text based system that asks you if you want various things turned on in the rescue environment such as networking (although they assume you want that these days) and if you want to attempt detection of installed Linux systems (which you do).

Drop out to the shell prompt and chroot to /mnt/sysimage.  Then rebuild the grub config (this is where os prober installed above comes in very handy) to include an entry for booting Win7.  Then re-install grub.  Job done.  Once you've booted to the rescue shell, the commands are something along the lines of:

  chroot /mnt/sysimage
  grub2-mkconfig > /boot/grub2/grub.cfg
  grub2-install /dev/sda
  exit
  exit
  reboot

This assumes you want to install grub to /dev/sda of course.  You'll need to exit (or ctrl+d) twice, once to get out of the chroot and once more to return to the rescue interface.  Then choose to reboot from there as it'll cleanly unmount your file systems and do a better job of clearing up than if you simply rebooted the system yourself.

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