Documentation Discrepancy - Manual Configuration

Documentation Discrepancy - Manual Configuration

[Dyweni - Ceph-Devel]

Hi,

Testing Ceph with 0.79.

1 Monitor
2 OSDs


Following the instructions here 
(http://ceph.com/docs/master/install/manual-deployment/)... I arrive at 
this state:

------
     cluster e3e1a87b-d282-41b5-b4ad-fb3f969e164f
      health HEALTH_WARN 192 pgs degraded; 192 pgs stuck unclean
      monmap e1: 1 mons at {a=10.208.39.100:6789/0}, election epoch 1, 
quorum 0 a
      osdmap e16: 2 osds: 2 up, 2 in
       pgmap v21: 192 pgs, 3 pools, 0 bytes data, 0 objects
             2004 MB used, 59381 MB / 65536 MB avail
                  192 active+degraded
------

'ceph osd dump' shows this:
------
...
pool 0 'data' replicated size 3 min_size 2 ...
pool 1 'metadata' replicated size 3 min_size 2 ...
pool 2 'rbd' replicated size 3 min_size 2 ...
...
------



It's not until I add a third OSD, or reduce the size of the pools, does 
the 192 pgs become unstuck and migrate towards active+clean.



I think the documentation should indicate that three nodes are required 
for Ceph to become optimal.



-- 
Thanks,
Dyweni

Re: Documentation Discrepancy - Manual Configuration

[Joao Eduardo Luis]

On 04/18/2014 08:10 AM, Dyweni - Ceph-Devel wrote:
> Hi,
>
> Testing Ceph with 0.79.
>
> 1 Monitor
> 2 OSDs
>
>
> Following the instructions here
> (http://ceph.com/docs/master/install/manual-deployment/)... I arrive at
> this state:
>
> ------
>      cluster e3e1a87b-d282-41b5-b4ad-fb3f969e164f
>       health HEALTH_WARN 192 pgs degraded; 192 pgs stuck unclean
>       monmap e1: 1 mons at {a=10.208.39.100:6789/0}, election epoch 1,
> quorum 0 a
>       osdmap e16: 2 osds: 2 up, 2 in
>        pgmap v21: 192 pgs, 3 pools, 0 bytes data, 0 objects
>              2004 MB used, 59381 MB / 65536 MB avail
>                   192 active+degraded

Indeed, ceph's default pool size is 3.  However, during the manual 
deployment guide you followed, on the "Monitor Bootstrap" section, 14th 
step, you certainly configured ceph.conf.  During this step, the guide 
presents you with an example configuration file containing the option 
'osd pool default size = 2', which overrides the default pool size of 3.

Furthermore, later during the 'Adding OSDs' section, this is made 
obvious right on the first paragraph.

Could this be made more obvious to a new-comer, probably.  But the info 
is there :)

   -Joao

>
> 'ceph osd dump' shows this:
> ------
> ...
> pool 0 'data' replicated size 3 min_size 2 ...
> pool 1 'metadata' replicated size 3 min_size 2 ...
> pool 2 'rbd' replicated size 3 min_size 2 ...
> ...
> ------
>
>
>
> It's not until I add a third OSD, or reduce the size of the pools, does
> the 192 pgs become unstuck and migrate towards active+clean.
>
>
>
> I think the documentation should indicate that three nodes are required
> for Ceph to become optimal.
>
>
>


-- 
Joao Eduardo Luis
Software Engineer | http://inktank.com | http://ceph.com