> Redhat/Micron/Samsung/Supermicro have all put out white papers backing the idea of 2 copies on NVMe's as safe for production. It's not like you can just jump from "unsafe" to "safe" -- it is about comparing the probability of losing data against how valuable that data is. A vendor's decision on size -- when they have a vested interest in making the price lower vs the competition -- may be a different decision than you would make as the person who stands to lose your data and potentially your career. And I say this as someone who works for a hardware vendor... listen to their advice but make your own decision. I have lost data on a size 2 cluster before and learned first-hand how easy it is for this to happen. Luckily it was just my home NAS. But if anyone has Roger Federer's 2018 tennis matches archived we need to talk :D Mark  On Wed, Feb 3, 2021 at 8:50 AM Adam Boyhan <adamb@xxxxxxxxxx> wrote: > > Isn't this somewhat reliant on the OSD type? > > Redhat/Micron/Samsung/Supermicro have all put out white papers backing the idea of 2 copies on NVMe's as safe for production. > > > From: "Magnus HAGDORN" <Magnus.Hagdorn@xxxxxxxx> > To: pseudo@xxxxxxxxxxxxx > Cc: "ceph-users" <ceph-users@xxxxxxx> > Sent: Wednesday, February 3, 2021 4:43:08 AM > Subject: Re: Worst thing that can happen if I have size= 2 > > On Wed, 2021-02-03 at 09:39 +0000, Max Krasilnikov wrote: > > > if a OSD becomes unavailble (broken disk, rebooting server) then > > > all > > > I/O to the PGs stored on that OSD will block until replication > > > level of > > > 2 is reached again. So, for a highly available cluster you need a > > > replication level of 3 > > > > > > AFAIK, with min_size 1 it is possible to write even to only active > > OSD serving > > > yes, that's correct but then you seriously risk trashing your data > > The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. > _______________________________________________ > 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 _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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