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-referen…
|
https://www.redhat.com/cms/managed-files/st-micron-ceph-performance-referen…
]
[
https://www.samsung.com/semiconductor/global.semi/file/resource/2020/05/red…
|
https://www.samsung.com/semiconductor/global.semi/file/resource/2020/05/red…
]
From: DHilsbos(a)performair.com
To: "adamb" <adamb(a)medent.com>
Cc: "ceph-users" <ceph-users(a)ceph.io>
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(a)PerformAir.com
www.PerformAir.com
-----Original Message-----
From: Adam Boyhan [mailto:adamb@medent.com]
Sent: Wednesday, February 3, 2021 8:50 AM
To: Magnus HAGDORN
Cc: ceph-users
Subject: [ceph-users] 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(a)ed.ac.uk>
To: pseudo(a)avalon.org.ua
Cc: "ceph-users" <ceph-users(a)ceph.io>
Sent: Wednesday, February 3, 2021 4:43:08 AM
Subject: [ceph-users] 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.
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