On 11/29/19 6:28 AM, jesper@xxxxxxxx wrote: > Hi Nathan > > Is that true? > > The time it takes to reallocate the primary pg delivers “downtime” by > design. right? Seen from a writing clients perspective > That is true. When an OSD goes down it will take a few seconds for it's Placement Groups to re-peer with the other OSDs. During that period writes to those PGs will stall for a couple of seconds. I wouldn't say it's 40s, but it can take ~10s. This is however by design. Consistency of data has a higher priority than availability inside Ceph. 'Nothing in this world is for free'. Keep that in mind. Wido > Jesper > > > > Sent from myMail for iOS > > > Friday, 29 November 2019, 06.24 +0100 from pengbo@xxxxxxxxxxx > <pengbo@xxxxxxxxxxx>: > > Hi Nathan, > > Thanks for the help. > My colleague will provide more details. > > BR > > On Fri, Nov 29, 2019 at 12:57 PM Nathan Fish <lordcirth@xxxxxxxxx > <mailto:lordcirth@xxxxxxxxx>> wrote: > > If correctly configured, your cluster should have zero downtime > from a > single OSD or node failure. What is your crush map? Are you using > replica or EC? If your 'min_size' is not smaller than 'size', > then you > will lose availability. > > On Thu, Nov 28, 2019 at 10:50 PM Peng Bo <pengbo@xxxxxxxxxxx > <mailto:pengbo@xxxxxxxxxxx>> wrote: > > > > Hi all, > > > > We are working on use CEPH to build our HA system, the purpose > is the system should always provide service even a node of CEPH > is down or OSD is lost. > > > > Currently, as we practiced once a node/OSD is down, the CEPH > cluster needs to take about 40 seconds to sync data, our system > can't provide service during that. > > > > My questions: > > > > Does there have any way that we can reduce the data sync time? > > How can we let the CEPH keeps available once a node/OSD is down? > > > > > > BR > > > > -- > > The modern Unified Communications provider > > > > https://www.portsip.com > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx <mailto:ceph-users@xxxxxxxxxxxxxx> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > -- > The modern Unified Communications provider > > https://www.portsip.com > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx <mailto:ceph-users@xxxxxxxxxxxxxx> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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