On 2011-10-10 09:17, Wen Congyang wrote: > At 10/10/2011 03:01 PM, Jan Kiszka Write: >> On 2011-10-10 08:59, Wen Congyang wrote: >>> At 10/10/2011 02:52 PM, Jan Kiszka Write: >>>> On 2011-10-10 04:21, Wen Congyang wrote: >>>>> At 10/09/2011 06:23 PM, Richard W.M. Jones Write: >>>>>> On Sun, Oct 09, 2011 at 10:49:57AM +0200, Jan Kiszka wrote: >>>>>>> As explained in the other replies: It is way more future-proof to use an >>>>>>> interface for this which was designed for it (remote gdb) instead of >>>>>>> artificially relaxing reasonable constraints of the migration mechanism >>>>>>> plus having to follow that format with the post-processing tool. >>>>>> >>>>>> Any interface that isn't "get this information off my production >>>>>> server *now*" so that I can get the server restarted, and send it to >>>>>> an expert to analyse -- is a poor interface, whether it was designed >>>>>> like that or not. Perhaps we don't have the right interface at all, >>>>>> but remote gdb is not it. >>>>> >>>>> What about the following idea? >>>>> >>>>> Introduce a new monitor command named dump, and this command accepts a >>>>> filename. >>>>> We can use almost all migration's code. We use this command to dump >>>>> guest's >>>>> memory, so there is no need to check whether the guest has a unmigratable >>>>> device. >>>> >>>> I do not want to reject this proposal categorically, but I would like to >>>> see the gdb path fail /wrt essential requirements first. So far I don't >>>> see it would. >>> >>> ‘gdb path fail /wrt essential requirements’ >>> >>> what does it mean? >> >> That you explain why reading reading memory and processor states via the >> remote gdb interface and dumping it into a proper core file cannot be >> made working for you. > > First, I think crash can not analyze such core file. But it is not very > important. > > What is remote gdb interface?
man qemu -> gdb. > Do you mean that: the supporter uses gdb from another machine Or locally. There are various transports possible. > to connect to customer's machine and get the data? If so, this way can not be > used when the customer needs to dump the guest's memory automatically when > watchdog timeouts. It is just another channel that can conceptually be used like the monitor, by a management app like libvirt, directly or indirectly via a scripted gdb frontend, or also by a human who wants to save some ongoing gdb session for later analysis. This dual use make such an approach the preferred one. Jan
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