On Thu, Nov 26, 2015 at 3:54 PM, hzwulibin <hzwulibin@xxxxxxxxx> wrote: > Hi, Sage > > I has a question about min_size of pool. > > The default value of min_size is 2, but in this setting, when two OSDs are down(mean two replicas lost) at same time, the IO will be blocked. > We want to set the min_size to 1 in our production environment as we think it's normal case when two OSDs are down(sure on different host) at same time. min_size with 2 means each object must ensure two copies in this pool. It mainly reduce the permanent storage media corrupt risk which cause actual data lose. That's mean if min_size is 1 and under this degraded case, one more osd permanent corrupt will cause data lose. If min_size is 2, it need at least 2 osds. > > So is there anypotential problem of this setting? > > We use 0.80.10 version. > > Thanks! > > > ------------------ > hzwulibin > 2015-11-26 > > ------------------------------------------------------------- > 发件人："hzwulibin"<hzwulibin@xxxxxxxxx> > 发送日期：2015-11-23 09:00 > 收件人：Sage Weil,Haomai Wang > 抄送：ceph-devel > 主题：Re: why my cluster become unavailable > > Hi, Sage > > Thanks! Will try it when next testing! > > ------------------ > hzwulibin > 2015-11-23 > > ------------------------------------------------------------- > 发件人：Sage Weil <sage@xxxxxxxxxxxx> > 发送日期：2015-11-22 01:49 > 收件人：Haomai Wang > 抄送：Libin Wu,ceph-devel > 主题：Re: why my cluster become unavailable > > On Sun, 22 Nov 2015, Haomai Wang wrote: >> On Thu, Nov 19, 2015 at 11:26 PM, Libin Wu <hzwulibin@xxxxxxxxx> wrote: >> > Hi, cepher >> > >> > I have a cluster of 6 OSD server, every server has 8 OSDs. >> > >> > I out 4 OSDs on every server, then my client io is blocking. >> > >> > I reboot my client and then create a new rbd device, but the new >> > device also can't write io. >> > >> > Yeah, i understand that some data may lost as threee replicas of some >> > object were lost, but why the cluster become unavailable? >> > >> > There 80 incomplete pg and 4 down+incomplete pg. >> > >> > Any solution i could solve the problem? >> >> Yes, if you doesn't have a special crushmap to control the data >> replcement policy, pg will lack of necessary metadata to boot. If need >> to readd outed osds or force remove pg which is incomplete(hope it's >> just a test). > > Is min_size 2 or 1? Reducing it to 1 will generally clear some of the > incomplete pgs. Just remember to raise it back to 2 after the cluster > recovers. > > sage > > -- Best Regards, Wheat -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
