On Thu, Jul 3, 2014 at 11:17 AM, Iban Cabrillo <cabrillo at ifca.unican.es> wrote:
> Hi Gregory,
> Thanks a lot I begin to understand who ceph works.
> I add a couple of osd servers, and balance the disk between them.
>
>
> [ceph at cephadm ceph-cloud]$ sudo ceph osd tree
> # id weight type name up/down reweight
> -7 16.2 root 4x1GbFCnlSAS
> -9 5.4 host node02
> 7 2.7 osd.7 up 1
> 8 2.7 osd.8 up 1
> -4 5.4 host node03
>
> 2 2.7 osd.2 up 1
> 9 2.7 osd.9 up 1
> -3 5.4 host node04
>
> 1 2.7 osd.1 up 1
> 10 2.7 osd.10 up 1
> -6 16.2 root 4x4GbFCnlSAS
>
> -5 5.4 host node01
> 3 2.7 osd.3 up 1
> 4 2.7 osd.4 up 1
> -8 5.4 host node02
> 5 2.7 osd.5 up 1
> 6 2.7 osd.6 up 1
> -2 5.4 host node04
>
> 0 2.7 osd.0 up 1
> 11 2.7 osd.11 up 1
> -1 32.4 root default
> -2 5.4 host node04
>
> 0 2.7 osd.0 up 1
> 11 2.7 osd.11 up 1
> -3 5.4 host node04
>
> 1 2.7 osd.1 up 1
> 10 2.7 osd.10 up 1
> -4 5.4 host node03
>
> 2 2.7 osd.2 up 1
> 9 2.7 osd.9 up 1
> -5 5.4 host node01
> 3 2.7 osd.3 up 1
> 4 2.7 osd.4 up 1
> -8 5.4 host node02
> 5 2.7 osd.5 up 1
> 6 2.7 osd.6 up 1
> -9 5.4 host node02
> 7 2.7 osd.7 up 1
> 8 2.7 osd.8 up 1
>
> The Idea Is to have at least 4 servers and 3 disk (2.7 TB SAN attached) for
> server per pool.
> Now i have to adjust the pg and pgp and make some performance test.
>
> PD which is the difference betwwwn chose ans choseleaf?
"choose" instructs the system to choose N different buckets of the
given type (where N is specified by the "firstn 0" block to be the
replication level, but could be 1: "firstn 1", or replication - 1:
"firstn -1"). Since you're saying "choose firstn 0 type host", that's
what you're getting out, and then you're emitting those 3 (by default)
hosts. But they aren't valid "devices" (OSDs), so it's not a valid
mapping; you're supposed to then say "choose firstn 1 device" or
similar.
"chooseleaf" instead tells the system to choose N different buckets,
and then descend from each of those buckets to a leaf ("device") in
the CRUSH hierarchy. It's a little more robust against different
mappings and failure conditions, so generally a better choice than
"choose" if you don't need the finer granularity provided by choose.
-Greg
Software Engineer #42 @ http://inktank.com | http://ceph.com
