On 07/10/2017 12:14 PM, Peter Rajnoha wrote: > On 07/10/2017 11:53 AM, Lennart Poettering wrote: >> On Mon, 10.07.17 11:37, David Disseldorp (ddiss@xxxxxxx) wrote: >> >>> Thanks for the feedback, Lennart... >>> >>> On Mon, 10 Jul 2017 10:38:38 +0200, Lennart Poettering wrote: >>> >>>> On Wed, 05.07.17 13:01, David Disseldorp (ddiss@xxxxxxx) wrote: >>>> >>>>> Ceph relies on by-partuuid symlinks, in order to locate the journal >>>>> partition from a given OSD partition. For details, see >>>>> http://tracker.ceph.com/issues/19489. >>>> >>>> This appears way too broad, as it would apply to all LVM and all other >>>> devices. >>>> >>>> It appears to me Ceph should do the same as LVM does for this, and >>>> ship its own set of rules, and be careful to only match against the >>>> actual devices it creates. >>> >>> We can certainly do this in a Ceph specific manner via the existing >>> 95-ceph-osd.rules, but my impression was that the by-partuuid symlinks >>> are "owned" by 60-persistent-storage.rules . >>> >>> If you don't think the existence of these symlinks for dm paths will be >>> of use to others then I'll go ahead and propose it as a Ceph only >>> change. >> >> Hmmm, so thinking about this again: "partuuid" is actually for GPT >> partition UUIDs if I recall recorrectly, they wouldn't be generated >> for DM devices anyway, since they are one layer removed from the GPT, >> so are you even sure this will do what you are asking for? >> >> But even if this actually works: DM links so far are created by the >> LVM/libdevicemapper/ packages, not by udev, and I don't think this >> should change. Hence, please talk to the LVM/libdevicemapper folks >> about this and ask them for including it. >> > > Yes, please, any rules for symlinks which should be created under > /dev/disk for DM devices (including all its subsystems like LVM, > mpath...) should go into 13-dm-disk.rules that is part of LVM/DM source > tree: > > https://sourceware.org/git/?p=lvm2.git;a=blob;f=udev/13-dm-disk.rules.in > > Now, when we create a partition over a DM device, there's a new mapping > created on top for each partition (either by calling kpartx manually or > by having it created by partitioning tool directly if it supports that). > So in this case, it's not the kernel directly who creates the > partitions, but they're simply another DM devices created on top of the > underlying DM device to represent these partitions. But I think that > doesn't matter - we should still create those symlinks for people to > still have a possibility to reference the device by its part uuid - I'll > fix 13-dm-disk.rules to include this. > Fixed here: https://sourceware.org/git/?p=lvm2.git;a=commit;h=c48149cf80c6582c2369bc7f8a33d794021d9dae -- Peter -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
