Hi, currently I'm using a Debian 5.0 with the 2.6.18.8-x86_64-linode10 kernel. I tried to upgrade it selecting the image 2.6.32-x86_64-linode11 (paravirt) in the linode manager, but I noticed a strange behaviour:
- with the free -m command it showed less RAM than the total amount, exactly 512 instead of 540MB. With the 2.6.18.8 kernel, free -m showed exactly 540 MB
- showing at the CPU graph, it's always over a 0,5-0,7%... nothing incredible, but with the 2.6.18.8 when the node was doing nothing, the CPU graph was at 0%... it's a little bit annoying.

So, in order to upgrade the kernel I ran the command aptitude search linux-image and this is the result:
[wopr  ~] aptitude search linux-image
v linux-image -
v linux-image-2.6 -
p linux-image-2.6-amd64 - Linux 2.6 image on AMD64
p linux-image-2.6-openvz-amd64 - Linux 2.6 image on AMD64, OpenVZ support
p linux-image-2.6-vserver-amd64 - Linux 2.6 image on AMD64, Linux-VServer su
p linux-image-2.6-xen-amd64 - Linux 2.6 image on AMD64, oldstyle Xen sup
p linux-image-2.6.26-1-amd64 - Linux 2.6.26 image on AMD64
p linux-image-2.6.26-1-openvz-amd - Linux 2.6.26 image on AMD64, OpenVZ suppor
p linux-image-2.6.26-1-vserver-am - Linux 2.6.26 image on AMD64, Linux-VServer
p linux-image-2.6.26-1-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen
p linux-image-2.6.26-2-amd64 - Linux 2.6.26 image on AMD64
p linux-image-2.6.26-2-openvz-amd - Linux 2.6.26 image on AMD64, OpenVZ suppor
p linux-image-2.6.26-2-vserver-am - Linux 2.6.26 image on AMD64, Linux-VServer
p linux-image-2.6.26-2-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen
p linux-image-amd64 - Linux image on AMD64
p linux-image-openvz-amd64 - Linux image on AMD64, OpenVZ support
p linux-image-vserver-amd64 - Linux image on AMD64, Linux-VServer suppor
p linux-image-xen-amd64 - Linux image on AMD64, oldstyle Xen support
[wopr  ~]

So, which one should I install among the four linux-image-2.6.26-2*?
Probably the "oldstyle Xen" one?
And another question: If I upgraded the kernel, once the linode should have to reboot, it would be replaced with the kernel indicated in my linode profile (2.6.18.8....)?

I hope to have been clear...

Thank you.

You'd need pv-grub

http://library.linode.com/advanced/pv-grub-howto

Thank you.

This doesn't seem like good justification to go through the trouble of using a custom kernel...



That's probably normal, just the kernel not including its memory or initrd memory or somesuch in the figure. My 32-bit 540 shows 526 MB of RAM total; your 512 MB figure is probably just a coincidence (and a bit lower than mine because it's 64-bit).



Eh. I've heard of that, but don't remember the details. It's really not very much CPU anyway...



I'm not sure what you mean. Unless you're using pv-grub, Xen complete ignores your /boot directory. You can put whatever you want in it, including other kernels. It does not dump a copy of Linode's kernel in /boot.

I'd agree, that's not really a good reason to be messing with custom kernels.

Sorry, I don't understand: are you suggesting me to install a newer kernel (via aptitude install...) or to maintain the "linode kernel"?
If the right way was the first one (keep kernel upgraded) which one should I choose?
Infact aptitutude search linux-image returns four possible linux-image... have I to install the last one, linux-image-2.6.26-2-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen?

Thank you

OP, what are you trying to do. You're asking a lot of questions, but it's completely unclear what your goal is.

Ok, I try to explain with my poor english:

My node is running a Debian 5.0 x64 with the "linode" kernel 2.6.18.8.

My goal is to keep my node always up to date, software and system.
Infact I think that an up-to-date system is more secure than a not updated one... isn't it?

So, if for the installed software I periodically run aptitude update/upgrade and manually update third-party software, for the system (the linux kernel) I don't know what the linode platform let me do to keep the kernel updated... I read just few hours ago about the pv_grub.
I think it can be the right way: install grub, the new linux-image and configure my node to use pv_grub.

My doubts are:
- linux-image-xen-amd64 is the right kernel to install?
- in your experience, do you think it's all wasted job, meaning that the linode kernel ( 2.6.18.8 ) is secure enough that it doesn't require this "manual" upgrade?

I hope to have clarified my goals and doubts... (I know, I need an advanced english course )

Given the "oldstyle Xen" description, I would guess that it uses the old Xen patches instead of pv_ops, making it the wrong kernel to install.



Yes, I think it's a waste of effort. Linode is not run by idiots. They do backport security patches to the 2.6.18 kernels when necessary, and the new pv_ops kernels are, well, new.

To keep the kernel up-to-date, set your configuration profile to use "Latest 2.6 Stable" or "Latest 2.6 Paravirt" and reboot whenever a new kernel comes out. Even ignoring the pv-grub stuff, that's still easier than maintaining Debian's kernel with aptitude.

Perfect... I think your post can close the argument!

Thank you all.