No problem. They have been around for quite some time now. Even speaking to the Ceph engineers over at supermicro while we spec'd our hardware, they agreed as well. [ https://www.supermicro.com/white_paper/white_paper_Ceph-Ultra.pdf | https://www.supermicro.com/white_paper/white_paper_Ceph-Ultra.pdf ] [ https://www.redhat.com/cms/managed-files/st-micron-ceph-performance-reference-architecture-f17294-201904-en.pdf | https://www.redhat.com/cms/managed-files/st-micron-ceph-performance-reference-architecture-f17294-201904-en.pdf ] [ https://www.samsung.com/semiconductor/global.semi/file/resource/2020/05/redhat-ceph-whitepaper-0521.pdf | https://www.samsung.com/semiconductor/global.semi/file/resource/2020/05/redhat-ceph-whitepaper-0521.pdf ] From: DHilsbos@xxxxxxxxxxxxxx To: "adamb" <adamb@xxxxxxxxxx> Cc: "ceph-users" <ceph-users@xxxxxxx> Sent: Wednesday, February 3, 2021 10:57:38 AM Subject: RE: Worst thing that can happen if I have size= 2 Adam; I'd like to see that / those white papers. I suspect what they're advocating is multiple OSD daemon processes per NVMe device. This is something which can improve performance. Though I've never done it, I believe you partition the device, and then create your OSD pointing at a partition. Thank you, Dominic L. Hilsbos, MBA Director - Information Technology Perform Air International Inc. DHilsbos@xxxxxxxxxxxxxx www.PerformAir.com -----Original Message----- From: Adam Boyhan [mailto:adamb@xxxxxxxxxx] Sent: Wednesday, February 3, 2021 8:50 AM To: Magnus HAGDORN Cc: ceph-users Subject: Re: Worst thing that can happen if I have size= 2 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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