On Thu, 01/12 15:39, Yang Zhang wrote: > On 2017/1/12 10:22, Fam Zheng wrote: > > On Thu, 01/12 09:22, Yang Zhang wrote: > > > On 2017/1/4 22:44, Stefan Hajnoczi wrote: > > > > On Tue, Jan 03, 2017 at 10:53:06AM -0600, Eric Blake wrote: > > > > > On 12/29/2016 08:41 PM, Junkang Fu wrote: > > > > > > >From 74e913fc41ea98d1dde692175f1e3fb6729342aa Mon Sep 17 00:00:00 > > > > > > >2001 > > > > > > From: "junkang.fjk" <junkang....@alibaba-inc.com> > > > > > > Date: Wed, 24 Aug 2016 19:36:53 +0800 > > > > > > Subject: [PATCH] virtio-blk: add disk-name device property > > > > > > > > > > > > Current virtio-blk disk name(ex. /dev/vdb) has nothing to do with > > > > > > the > > > > > > target dev > > > > > > name specified in libvirt xml file. For example, we may get disk > > > > > > name > > > > > > /dev/vdb in > > > > > > VM while target dev specified in libvirt xml is vdc. > > > > > > > > > > It's not really libvirt's fault. The libvirt XML names are for > > > > > convenience, but nothing on the host side requires the guest to pick > > > > > the > > > > > same naming scheme as the host. > > > > > > > > > > I guess your proposal is to enhance the virtio spec such that clients > > > > > that are new enough to honor the new addition to the virtio spec will > > > > > change their name-picking algorithm to use the name provided by the > > > > > host, rather than their current approach of picking whatever name they > > > > > feel like, and then enhance libvirt to pass the XML name on down to > > > > > the > > > > > guest? It might work, but as others have pointed out, it will > > > > > require a > > > > > virtio spec change first. > > > > > > > > This change is unnecessary. The -device virtio-blk-pci,serial= property > > > > already exists for this purpose. > > > > > > how about the /dev/vdabc? I guess lots of people prefer to use it instead > > > of > > > /dev/disk/by-id/xxx? > > > > I disagree. Using /dev/sdX has exactly the same issue and that's why fstab > > and > > boot loader etc almost always use UUID or disk label by default because > > they are > > more stable. > > I mean does it also change the /dev/sdX to the name specified in serial=sdX > or it just show the name under /dev/disk/by-id/
I was saying on real hardware, sata disks can have unstable /dev/sdX naming across reboots if you add or remove disks on the controller, or add or remove HBA. Fam
