Hello Adam, 2 copies are save, min size 1 is not. As long as there is no write while one copy is missing, you can recover from that or from the unavailable copy when it comes online again. If you have min size 1 and you therefore write data on a single copy, no safety net will protect you. In general we consider even a 2 copy setup not secure enough. -- Martin Verges Managing director Mobile: +49 174 9335695 E-Mail: martin.verges@xxxxxxxx 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 Am Mi., 3. Feb. 2021 um 16:50 Uhr schrieb Adam Boyhan <adamb@xxxxxxxxxx>: > > 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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