On Tue, 2010-07-27 at 21:41 +0100, Pasi Kärkkäinen wrote:
> > Backward compatible disk configuration
> > --------------------------------------
> >
> > Given the above configuration options several short hands are
> defined
> > for backwards compatibility with existing configuration files and
> > guests.
> >
> > These will be implemented by a straight textual substitution before
> > parsing the configuration.
> >
> > hda => d0p0,pv=true,emul=ide0.0,_vdevice=3:0
> > hdb => d1p0,pv=true,emul=ide0.1,_vdevice=3:64
> > hdc => d2p0,pv=true,emul=ide1.0,_vdevice=22:0
> > hdd => d3p0,pv=true,emul=ide1.1,_vdevice=22:64
> >
> > xvda => d0p0,pv=true,emul=_ide0.0,_vdevice=202:0
> > xvdb => d1p0,pv=true,emul=_ide0.1,_vdevice=202:16
> > xvdc => d2p0,pv=true,emul=_ide1.0,_vdevice=202:32
> > xvdd => d3p0,pv=true,emul=_ide1.1,_vdevice=202:64
> > xvde => d4p0,pv=true,emul=none,_vdevice=202:80
> > ...
> > xvdo => d15p0,pv=true,emul=none,_vdevice=202:240
> > xvdp => d16p0,pv=true,emul=none
> > ...
> > xvdz => d25,pv=true,emul=none
> >
> > xvda[1..15] =>
> > d0p[1..15],pv=true,emul=_ide0.0,_vdevice=202:[0..15]
> > xvdb[1..15] => etc
> >
> > Note that all the above are Linux (guest) specific.
> >
> > The sd* syntax is not covered. It's unclear if this is used in the
> > wild or what the existing semantics of emul= are for SCSI devices.
> > If someone cares to investigate the existing behaviour then it can
> > be added.
> >
>
> sd* devices are still often used for Xen PV domUs..
> (yeah, people should use xvd*, but many people still have sd*).
Thanks. We can therefore add to the shorthands (emul=none unless anyone
knows better):
sda => d0p0,pv=true,emul=none,_vdevice=8:0
sdb => d1p0,pv=true,emul=none,_vdevice=8:16
sdc => d2p0,pv=true,emul=none,_vdevice=8:32
sdd => d3p0,pv=true,emul=none,_vdevice=8:48
...
sdp => d15p0,pv=true,emul=none,_vdevice=8:240
sdq => d16p0,pv=true,emul=none,_vdevice=65:0
sdr => d17p0,pv=true,emul=none,_vdevice=65:16
... etc through:
... ... major 65 (sdq ->sdaf)
... ... major 66 (sdag->sdav)
... ... major 67 (sdaw->sdbl)
... ... major 68 (sdbm->sdcr)
... ... major 69 (sdcc->sdcr)
... ... major 70 (sdcs->sddh)
... ... major 71 (sddi->sddx)
sddx => d127p0,pv=true,emul=none,_vdevice=71:240
(perhaps supporting all these is overkill ;-))
Ian.
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