Hi Federico, here I am not mixing raid1 with ceph. I am doing a comparison: is it safer to have a server with raid1 disks or two servers with ceph and size=2 min_size=1 ? We are talking about real world examples where a customer is buying a new server and want to choose. Il giorno gio 4 feb 2021 alle ore 05:52 Federico Lucifredi < federico@xxxxxxxxxx> ha scritto: > Ciao Mario, > > >> It is obvious and a bit paranoid because many servers on many customers >> run >> on raid1 and so you are saying: yeah you have two copies of the data but >> you can broke both. Consider that in ceph recovery is automatic, with >> raid1 >> some one must manually go to the customer and change disks. So ceph is >> already an improvement in this case even with size=2. With size 3 and min >> 2 >> it is a bigger improvement I know. >> > > Generally speaking, users running Ceph at any scale do not use RAID to > mirror their drives. They rely on data resiliency as delivered by Ceph > (three replicas on HDD, two replicas on solid state media). > > It is expensive to run RAID underneath Ceph, and in some cases even > counter-productive. We do use RAID controllers whenever we can because they > are battery-backed and insure writes hit the local disk even on a power > failure, but that is (ideally) the only case where you hear the words RAID > and Ceph together. > > -- "'Problem' is a bleak word for challenge" - Richard Fish > _________________________________________ > Federico Lucifredi > Product Management Director, Ceph Storage Platform > Red Hat > A273 4F57 58C0 7FE8 838D 4F87 AEEB EC18 4A73 88AC > redhat.com TRIED. TESTED. TRUSTED. > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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