ceph balancer status
ceph config-key dump | grep balancer
ceph osd dump | grep min_compat_client
ceph osd crush dump | grep straw
ceph osd crush dump | grep profile
ceph features

You didn't mention it, but based on your error and my experiences over the
last week getting the balancer working, you're trying to use crush-compat.
Running all of those commands should give you the information you need to
fix everything up for the balancer to work.  With the first 2, you need to
make sure that you have your mode set properly as well as double check any
other settings you're going for with the balancer.  Everything else stems
off of a requirement of having your buckets being straw2 instead of straw
for the balancer to work.  I'm sure you'll notice that your cluster has
older compatibility requirements and crush profile than hammer and that
your buckets are using the straw algorithm instead of straw2.

Running [1] these commands will fix up your cluster so that you are now
using straw2 and have your minimum required clients and profile to hammer
which is the ceph release that introduced straw2.  Before running these
commands make sure that the output of `ceph features` does not show any
firefly clients connected to your cluster.  If you do have any, it is
likely due to outdated kernels or clients installed without the upstream
ceph repo and just using the version of ceph in the canonical repos or
similar for your distribution.  If you do happen to have any firefly, or
older, clients connected to your cluster, then you need to update those
clients before running the commands.

There will be some data movement, but I didn't see more than ~5% data
movement on any of the 8 clusters I ran them on.  That data movement will
be higher if you do not have a standard size of OSD drive in your clusters
like some 2TB disks and some 8TB disks across your cluster will probably
cause some more data movement then I saw, but it should still be within
reason.  This data movement is because straw2 can handle that situation
better than straw did and will allow your cluster to better balance itself
even without the balancer module.

If you don't even have any hammer clients, then go ahead and set the
min-compat-client to jewel as well as the crush tunables to jewel.  Setting
them to Jewel will cause a bit more data movement, but again for good
reasons.

The tl;dr of your error is that your cluster has been running since at
least hammer which started with older default settings than are required by
the balancer module.  As you've updated your cluster you didn't allow it to
utilize new features in the backend by leaving your crush tunables alone
during all of the upgrades to new versions.  To learn more about the
changes to the crush tunables you can check out the ceph wiki [2] here.

[1]
ceph osd set-require-min-compat-client hammer
ceph osd crush set-all-straw-buckets-to-straw2
ceph osd crush tunables hammer

[2] http://docs.ceph.com/docs/master/rados/operations/crush-map/

On Tue, Sep 11, 2018 at 6:24 AM Marc Roos <m.r...@f1-outsourcing.eu> wrote:

>
> I am new, with using the balancer, I think this should generated a plan
> not? Do not get what this error is about.
>
>
> [@c01 ~]# ceph balancer optimize balancer-test.plan
> Error EAGAIN: compat weight-set not available
> _______________________________________________
> ceph-users mailing list
> ceph-users@lists.ceph.com
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
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