[libvirt] [PATCH v3 21/21] blkiotune: allow <node major='' minor=''/> in place of <path>

Daniel P. Berrange berrange at redhat.com
Tue Feb 11 14:55:06 UTC 2014


On Wed, Feb 05, 2014 at 03:10:19PM +0100, Cédric Bosdonnat wrote:
> To ease LXC configuration conversion, allow blkiotune device XML
> fragments to define the device using its major:minor numbers.
> ---
>  docs/formatdomain.html.in                       |  10 +-
>  src/conf/domain_conf.c                          |  45 ++++++++-
>  src/conf/domain_conf.h                          |   2 +
>  src/lxc/lxc_cgroup.c                            |   5 +
>  src/lxc/lxc_driver.c                            |  10 ++
>  src/lxc/lxc_native.c                            |  24 ++++-
>  src/qemu/qemu_cgroup.c                          |   5 +
>  src/qemu/qemu_driver.c                          |  10 ++
>  src/util/vircgroup.c                            | 126 ++++++++++--------------
>  src/util/vircgroup.h                            |  10 ++
>  tests/lxcconf2xmldata/lxcconf2xml-blkiotune.xml |   4 +-
>  11 files changed, 165 insertions(+), 86 deletions(-)
> 
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index fd02864..2ab7d39 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -761,6 +761,10 @@
>        <path>/dev/sdb</path>
>        <weight>500</weight>
>      </device>
> +    <device>
> +      <node major='8' minor='0'/>
> +      <weight>500</weight>
> +    </device>
>    </blkiotune>

I realize this is helping the conversion of existing configs, but
personally I'm pretty loathe to add this syntax. With device paths
it is possible to have stable paths ie using /dev/disk/by*. With
major/minor the XML configuration is not portable across hosts or
even stable  within a host since major numbers are fairly arbitrarily
assigned with hotpluggable SCSI or networked iSCSI.

Personally I'd list this as one of the things an admin has to fixup
manually post conversion.

Daniel
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