Hi Martin, Agreed on the min_size of 2. I have no intention of worrying about uptime in event of a host failure. Once size of 2 is effectuated (and I'm unsure how long it will take), it is our intention to evacuate all OSDs in one of 4 hosts, in order to migrate the host to the new cluster, where its OSDs will then be added in. Once added and balanced, we will complete the copies (<3 days) and then migrate one more host allowing us to bring size to 3. Once balanced, we will collapse the last 2 nodes into the new cluster. I am hoping that inclusive of rebalancing the whole project will only take 3 weeks, but time will tell. Has anyone asked Ceph to reduce hundreds of millions if not billions of files from size 3 to size 2, and if so, were you successful? I know it *should* be able to do this, but sometimes theory and practice don't perfectly overlap. Thanks, Marco On Sat, Dec 11, 2021 at 4:37 AM Martin Verges <martin.verges@xxxxxxxx> wrote: > Hello, > > avoid size 2 whenever you can. As long as you know that you might lose > data, it can be an acceptable risk while migrating the cluster. We had that > in the past multiple time and it is a valid use case in our opinion. > However make sure to monitor the state and recover as fast as possible. > Leave min_size on 2 as well and accept the potential downtime! > > -- > Martin Verges > Managing director > > Mobile: +49 174 9335695 | Chat: https://t.me/MartinVerges > > croit GmbH, Freseniusstr. 31h, 81247 Munich > CEO: Martin Verges - VAT-ID: DE310638492 > Com. register: Amtsgericht Munich HRB 231263 > Web: https://croit.io | YouTube: https://goo.gl/PGE1Bx > > > On Fri, 10 Dec 2021 at 18:05, Marco Pizzolo <marcopizzolo@xxxxxxxxx> > wrote: > >> Hello, >> >> As part of a migration process where we will be swinging Ceph hosts from >> one cluster to another we need to reduce the size from 3 to 2 in order to >> shrink the footprint sufficiently to allow safe removal of an OSD/Mon >> node. >> >> The cluster has about 500M objects as per dashboard, and is about 1.5PB in >> size comprised solely of small files served through CephFS to Samba. >> >> Has anyone encountered a similar situation? What (if any) problems did >> you >> face? >> >> Ceph 14.2.22 bare metal deployment on Centos. >> >> Thanks in advance. >> >> Marco >> _______________________________________________ >> ceph-users mailing list -- ceph-users@xxxxxxx >> To unsubscribe send an email to ceph-users-leave@xxxxxxx >> > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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