Re: Multiple rbd images from different clusters

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On Wed, Jun 5, 2019 at 12:59 PM Jordan Share <readmail@xxxxxxxxxx> wrote:
>
> One thing to keep in mind when pipelining rbd export/import is that the
> default is just a raw image dump.
>
> So if you have a large, but not very full, RBD, you will dump all those
> zeroes into the pipeline.
>
> In our case, it was actually faster to write to a (sparse) temp file and
> read it in again afterwards than to pipeline.
>
> However, we are not using --export-format 2, which I now suspect would
> mitigate this.

It's supposed to help since it's only using diffs -- never the full
image export.

> Jordan
>
>
> On 6/5/2019 8:30 AM, CUZA Frédéric wrote:
> > Hi,
> >
> > Thank you all for you quick answer.
> > I think that will solve our problem.
> >
> > This is what we came up with this :
> > rbd -c /etc/ceph/Oceph.conf --keyring /etc/ceph/Oceph.client.admin.keyring export rbd/disk_test - | rbd -c /etc/ceph/Nceph.conf --keyring /etc/ceph/Nceph.client.admin.keyring import - rbd/disk_test
> >
> > This rbd image is a test with only 5Gb of datas inside of it.
> >
> > Unfortunately the command seems to be stuck and nothing happens, both ports 7800 / 6789 / 22.
> >
> > We can't find no logs on any monitors.
> >
> > Thanks !
> >
> > -----Message d'origine-----
> > De : ceph-users <ceph-users-bounces@xxxxxxxxxxxxxx> De la part de Jason Dillaman
> > Envoyé : 04 June 2019 14:11
> > À : Burkhard Linke <Burkhard.Linke@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> > Cc : ceph-users <ceph-users@xxxxxxxxxxxxxx>
> > Objet : Re:  Multiple rbd images from different clusters
> >
> > On Tue, Jun 4, 2019 at 8:07 AM Jason Dillaman <jdillama@xxxxxxxxxx> wrote:
> >>
> >> On Tue, Jun 4, 2019 at 4:45 AM Burkhard Linke
> >> <Burkhard.Linke@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >>>
> >>> Hi,
> >>>
> >>> On 6/4/19 10:12 AM, CUZA Frédéric wrote:
> >>>
> >>> Hi everyone,
> >>>
> >>>
> >>>
> >>> We want to migrate datas from one cluster (Hammer) to a new one (Mimic). We do not wish to upgrade the actual cluster as all the hardware is EOS and we upgrade the configuration of the servers.
> >>>
> >>> We can’t find a “proper” way to mount two rbd images from two different cluster on the same host.
> >>>
> >>> Does anyone know what is the “good” procedure to achieve this ?
> >>
> >> Copy your "/etc/ceph/ceph.conf" and associated keyrings for both
> >> clusters to a single machine (preferably running a Mimic "rbd" client)
> >> under "/etc/ceph/<cluster-name>.conf" and
> >> "/etc/ceph/<cluster-name>.client.<id>.keyring".
> >>
> >> You can then use "rbd -c <old cluster name> export --export-format 2
> >> <image-spec> - | rbd -c <new cluster name> import --export-format=2 -
> >> <image-spec>". The "--export-format=2" option will also copy all
> >> associated snapshots with the images. If you don't want/need the
> >> snapshots, just drop that optional.
> >
> > That "-c" should be "--cluster" if specifying by name, otherwise with "-c" it's the full path to the two different conf files.
> >
> >>>
> >>> Just my 2 ct:
> >>>
> >>> the 'rbd' commands allows specifying a configuration file (-c). You need to setup two configuration files, one for each cluster. You can also use two different cluster names (--cluster option). AFAIK the name is only used to locate the configuration file. I'm not sure how well the kernel works with mapping RBDs from two different cluster.....
> >>>
> >>>
> >>> If you only want to transfer RBDs from one cluster to another, you do not need to map and mount them; the 'rbd' command has the sub commands 'export' and 'import'. You can pipe them to avoid writing data to a local disk. This should be the fastest way to transfer the RBDs.
> >>>
> >>>
> >>> Regards,
> >>>
> >>> Burkhard
> >>>
> >>> --
> >>> Dr. rer. nat. Burkhard Linke
> >>> Bioinformatics and Systems Biology
> >>> Justus-Liebig-University Giessen
> >>> 35392 Giessen, Germany
> >>> Phone: (+49) (0)641 9935810
> >>>
> >>> _______________________________________________
> >>> ceph-users mailing list
> >>> ceph-users@xxxxxxxxxxxxxx
> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >>
> >>
> >>
> >> --
> >> Jason
> >
> >
> >
> > --
> > Jason
> > _______________________________________________
> > ceph-users mailing list
> > ceph-users@xxxxxxxxxxxxxx
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> > _______________________________________________
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> >
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-- 
Jason
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