From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: kexec and kdump on Xen?? Date: Fri, 18 Apr 2014 17:26:05 +0100 Message-ID: <5351521D.8070804@citrix.com> References: <20140414081126.GA1632@router-fw-old.local.net-space.pl> <20140414132632.GA6173@router-fw-old.local.net-space.pl> <20140416111005.GA6251@router-fw-old.local.net-space.pl> <534FA3DB.3070103@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Zhang, Yang Z" Cc: "david.vrabel@citrix.com" , Daniel Kiper , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org 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