Red Hat Bugzilla – Bug 1275994
Incorrect recommendation on pg_num and pgp_num settings in installation guide
Last modified: 2016-03-01 03:21:54 EST
Description of problem:
In the RHCS 1.3 installation guide it is recommended to set osd_pool_default_pg_num and osd_pool_default_pgp_num to a too high number, causing too many PGs
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. install RHCS using the steps described in the manual
2. configure ceph.conf as described in chapter 7 including osd_pool_default_pg_num and osd_pool_default_pgp_num.
3. install rgw and start (which will create all rgw pools automatically using the values defined in step 3
too many pgs (e.g. 21000+ for 50 OSD cluster)
approx. 2000 pgs for a 50 OSD cluster
According to Tyler Brekke the osd_pool_default_pg_num and osd_pool_default_pg_num are never set up, and definitely not with these kind of high numbers. Recommendation is to use lower numbers and create all rgw pools manually.
The comments were only present in the 1.3 branch. These were removed as evidenced here:
We have a downstream version of PGCALC now, and the maximum pg value is sometimes hit when people set up an RGW instance. I've modified the appropriate sections to point to the PG calculator page, and also provided guidance on the max pgs per osd warning there too.
Verified the cephpgc link in the Document.. Looks good..
I would like to see the same procedure/pgcalc link in Ubuntu Install Guide also..
Marking it Verified.
Added the pgc calculator link in Ubuntu installation as well.