Hello, > 21 мая 2018 г., в 2:05, Sage Weil <[email protected]> написал(а): > > On Sun, 20 May 2018, Mike A wrote: >> Hello! >> >> In our cluster, we see a deadlock situation. >> This is a standard cluster for an OpenStack without a RadosGW, we have a >> standard block access pools and one for metrics from a gnocchi. >> The amount of data in the gnocchi pool is small, but objects are just a lot. >> >> When planning a distribution of PG between pools, the PG are distributed >> depending on the estimated data size of each pool. Correspondingly, as >> suggested by pgcalc for the gnocchi pool, it is necessary to allocate a >> little PG quantity. >> >> As a result, the cluster is constantly hanging with the error "1 pools have >> many more objects per pg than average" and this is understandable: the >> gnocchi produces a lot of small objects and in comparison with the rest of >> pools it is tens times larger. >> >> And here we are at a deadlock: >> 1. We can not increase the amount of PG on the gnocchi pool, since it is >> very small in data size >> 2. Even if we increase the number of PG - we can cross the recommended 200 >> PGs limit for each OSD in cluster >> 3. Constantly holding the cluster in the HEALTH_WARN mode is a bad idea >> 4. We can set the parameter "mon pg warn max object skew", but we do not >> know how the Ceph will work when there is one pool with a huge object / pool >> ratio >> >> There is no obvious solution. >> >> How to solve this problem correctly? > > As a workaround, I'd just increase the skew option to make the warning go > away. > > It seems to me like the underlying problem is that we're looking at object > count vs pg count, but ignoring the object sizes. Unfortunately it's a > bit awkward to fix because we don't have a way to quantify the size of > omap objects via the stats (currently). So for now, just adjust the skew > value enough to make the warning go away! > > sage
Ok. It seems that increase this config option, is the only acceptable option. Thank! — Mike, runs! _______________________________________________ ceph-users mailing list [email protected] http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
