On 01/20/2016 06:07 AM, Nick Fisk wrote: > Thanks for your input Mike, a couple of questions if I may > > 1. Are you saying that this rbd backing store is not in mainline and is only > in SUSE kernels? Ie can I use this lrbd on Debian/Ubuntu/CentOS?
The target_core_rbd backing store is not upstream and only in SUSE kernels. lrbd is the management tool that basically distributes the configuration info to the nodes you want to run LIO on. In that README you see it uses the target_core_rbd module by default, but last I looked there is code to support iblock too. So you should be able to use this with other distros that do not have target_core_rbd. When I was done porting my code to a iblock based approach I was going to test out the lrbd iblock support and fix it up if it needed anything. > 2. Does this have any positive effect on the abort/reset death loop a number > of us were seeing when using LIO+krbd and ESXi? The old code and my new approach does not really help. However, on Monday, Ilya and I were talking about this problem, and he gave me some hints on how to add code to cancel/cleanup commands so we will be able to handle aborts/resets properly and so we will not fall into that problem. > 3. Can you still use something like bcache over the krbd? Not initially. I had been doing active/active across nodes by default, so you cannot use bcache and krbd as is like that. > > > >> -----Original Message----- >> From: Mike Christie [mailto:mchri...@redhat.com] >> Sent: 19 January 2016 21:34 >> To: Василий Ангапов <anga...@gmail.com>; Ilya Dryomov >> <idryo...@gmail.com> >> Cc: Nick Fisk <n...@fisk.me.uk>; Tyler Bishop >> <tyler.bis...@beyondhosting.net>; Dominik Zalewski >> <dzalew...@optlink.co.uk>; ceph-users <ceph-users@lists.ceph.com> >> Subject: Re: [ceph-users] CentOS 7 iscsi gateway using lrbd >> >> Everyone is right - sort of :) >> >> It is that target_core_rbd module that I made that was rejected upstream, >> along with modifications from SUSE which added persistent reservations >> support. I also made some modifications to rbd so target_core_rbd and krbd >> could share code. target_core_rbd uses rbd like a lib. And it is also >> modifications to the targetcli related tool and libs, so you can use them to >> control the new rbd backend. SUSE's lrbd then handles setup/management >> of across multiple targets/gatways. >> >> I was going to modify targetcli more and have the user just pass in the rbd >> info there, but did not get finished. That is why in that suse stuff you >> still >> make the krbd device like normal. You then pass that to the target_core_rbd >> module with targetcli and that is how that module knows about the rbd >> device. >> >> The target_core_rbd module was rejected upstream, so I stopped >> development and am working on the approach suggested by those >> reviewers which instead of going from lio->target_core_rbd->krbd goes >> lio->target_core_iblock->linux block layer->krbd. With this approach you >> just use the normal old iblock driver and krbd and then I am modifying them >> to just work and do the right thing. >> >> >> On 01/19/2016 05:45 AM, Василий Ангапов wrote: >>> So is it a different approach that was used here by Mike Christie: >>> http://www.spinics.net/lists/target-devel/msg10330.html ? >>> It seems to be a confusion because it also implements target_core_rbd >>> module. Or not? >>> >>> 2016-01-19 18:01 GMT+08:00 Ilya Dryomov <idryo...@gmail.com>: >>>> On Tue, Jan 19, 2016 at 10:34 AM, Nick Fisk <n...@fisk.me.uk> wrote: >>>>> But interestingly enough, if you look down to where they run the >> targetcli ls, it shows a RBD backing store. >>>>> >>>>> Maybe it's using the krbd driver to actually do the Ceph side of the >> communication, but lio plugs into this rather than just talking to a dumb >> block >> device??? >>>> >>>> It does use krbd driver. >>>> >>>> Thanks, >>>> >>>> Ilya > > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
