Re: kexec and kdump on Xen??

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 18/04/14 02:45, Zhang, Yang Z wrote:
> Andrew Cooper wrote on 2014-04-17:
>> On 17/04/14 02:19, Zhang, Yang Z wrote:
>> As for real examples,  XenServer unconditionally sets up a native
>> crash kernel and does use it in the case of a Xen/dom0 crash.  It does
>> work reliably and repeatedly[1] and is routinely tested.
> I think XenServer uses the old approach to do the kexec.

Older versions of XenServer did.  While investigating an issue, David
discovered quite how broken^W fragile it was and reimplemented the Xen
side, which is the code present in Xen 4.4

We then backported the Xen side fixes to XenServer 6.2, which otherwise
uses Xen 4.1.5 and 2.6.32-classic dom0.

Since doing so, I am not aware of a single customer crash report which
has arrived without proper set of crash logs, taken from the crash
environment.

> What I am trying is the new kexec/kdump feature which enabled in Xen4.4. 
> One question, I remember kexec support is missing in 2.6.32-pvops kernel. If XenServer works well, do you know where can I find the patch to enable it for 2.6.32 kernel?

It is, but that is the point.  The new Xen 4.4 code bypasses the dom0
kernel entirely, and /sbin/kexec uses a libxc interface for loading the
hypervisor crash/load images.

~Andrew