64-bit guests

This article explains why, if you haven't already done so, you should switch to a 64-bit guest.

64-bit is default at BitFolk

If you've been a customer for less than 4 years then (unless you went out of your way to change this) your VM is already 64-bit, as the default was switched around that time.

Those who have kept the same account for longer than this quite possibly are still running 32-bit. If you are, you should start to think about how and when you will change over to 64-bit. Here's why.

Reasons to switch

1. 32-bit x86 isn't getting much upstream kernel attention

   There are multiple reports of 32-bit-only bugs being ignored in the upstream Linux kernel because no one is interested in working on them.

2. 32-bit Linux is less secure

   Possibly as a consequence of the above, 32-bit Linux lags behind even on security fixes. For example, full Spectre and Meltdown mitigations were in the 4.13 kernel for the amd64 architecture, but didn't arrive in the i686 kernel until 4.19.

3. More and more Linux distributions are dropping 32-bit support

   So far we're talking at least CentOS, Fedora and Ubuntu. Debian talk about it from time to time, too.

4. Xen has deprecated 32-bit PV guest support, too

   Xen, the hypervisor software we use, has indicated that 32-bit PV guest support is now deprecated, and will be removed after a release or two, which probably means a couple of years. This isn't the end of the world because we will by then have switched to PVH guests which will be able to run 32-bit guests. However it's probably not a good idea to make things more complicated.

How to tell what you're running

There's three different places where the architecture of a BitFolk VM matters:

1. The bootloader
2. The kernel
3. The rest of the operating system ("userland")

You can see which architecture of bootloader you have by looking at the summary page of the BitFolk Panel, or using the "arch" command of the Xen Shell. You can only boot kernels of the same architecture as your bootloader, so a working VM will have a bootloader of the same architecture as the kernel.

The architecture of your kernel should show up in your package manager and the output of the uname -a command.

64-bit kernels can run both 32- and 64-bit binaries, so possibly you have a mixture in the rest of your operating system. Your package manager should tell you, but presumably you would know if you had done this.

How to switch to 64-bit

So you have a 32-bit guest but you want to end up with a 64-bit one.