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Juergen Gross
6338c9ead9
debugtrace is normally writing trace entries into a single trace buffer. There are cases where this is not optimal, e.g. when hunting a bug which requires writing lots of trace entries and one cpu is stuck. This will result in other cpus filling the trace buffer and finally overwriting the interesting trace entries of the hanging cpu. In order to be able to debug such situations add the capability to use per-cpu trace buffers. This can be selected by specifying the debugtrace boot parameter with the modifier "cpu:", like: debugtrace=cpu:16 At the same time switch the parsing function to accept size modifiers (e.g. 4M or 1G). Printing out the trace entries is done for each buffer in order to minimize the effort needed during printing. As each entry is prefixed with its sequence number sorting the entries can easily be done when analyzing them. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Remus provides fault tolerance for virtual machines by sending continuous checkpoints to a backup, which will activate if the target VM fails. See the website at http://wiki.xen.org/wiki/Remus for details. Using Remus with libxl on Xen 4.5 and higher: To enable network buffering, you need libnl 3.2.8 or higher along with the development headers and command line utilities. If your distro does not have the appropriate libnl3 version, you can find the latest source tarball of libnl3 at http://www.carisma.slowglass.com/~tgr/libnl/ Disk replication: VMs protected by Remus need to use DRBD based disk backends. Specifically, you need a compile and install a custom version of DRBD, that is available publicly at https://github.com/rshriram/remus-drbd This code is based on DRBD 8.3.11 and uses a new replication protocol (named protocol D) for asynchronous disk checkpoint replication. A protected VM's DRBD disks on the primary and backup hosts need to be configured to use protocol D as the replication protocol. An example resource configuration file can be found in the aforementioned github repository.