Marcel; Sorry, could also send the output of: ceph osd tree Thank you, Dominic L. Hilsbos, MBA Director - Information Technology Perform Air International, Inc. DHilsbos@PerformAir.com www.PerformAir.com -----Original Message----- From: DHilsbos@performair.com [mailto:DHilsbos@performair.com] Sent: Tuesday, July 21, 2020 9:41 AM To: ceph@mknet.nl; ceph-users@ceph.io Subject: [ceph-users] Re: osd out vs crush reweight] Marcel; Thank you for the information. Could you send the output of: ceph osd crush rule dump Thank you, Dominic L. Hilsbos, MBA Director - Information Technology Perform Air International, Inc. DHilsbos@PerformAir.com www.PerformAir.com -----Original Message----- From: Marcel Kuiper [mailto:ceph@mknet.nl] Sent: Tuesday, July 21, 2020 9:38 AM To: ceph-users@ceph.io Subject: [ceph-users] Re: osd out vs crush reweight] Hi Dominic, This cluster is running 14.2.8 (nautilus) There's 172 osds divided over 19 nodes. There are currently 10 pools. All pools have 3 replica's of data There are 3968 PG's (the cluster is not yet fully in use. The number of PGs is expected to grow) Marcel
Marcel;
Short answer; yes, it might be expected behavior.
PG placement is highly dependent on the cluster layout, and CRUSH rules. So... Some clarifying questions.
What version of Ceph are you running? How many nodes do you have? How many pools do you have, and what are their failure domains?
Thank you,
Dominic L. Hilsbos, MBA Director - Information Technology Perform Air International, Inc. DHilsbos@PerformAir.com www.PerformAir.com
-----Original Message----- From: Marcel Kuiper [mailto:ceph@mknet.nl] Sent: Tuesday, July 21, 2020 6:52 AM To: ceph-users@ceph.io Subject: [ceph-users] osd out vs crush reweight
Hi list,
I ran a test with marking an osd out versus setting its crush weight to 0. I compared to what osds pages were send. The crush map has 3 rooms. This is what happened.
On ceph osd out 111 (first room; this node has osds 108 - 116) pg's were send to the following osds
NR PG's OSD 2 1 1 4 1 5 1 6 1 7 2 8 1 31 1 34 1 35 1 56 2 57 1 58 1 61 1 83 1 84 1 88 1 99 1 100 2 107 1 114 2 117 1 118 1 119 1 121
All PG's were send to osds on other nodes in the same room, except for 1 PG on osd 114. I think this works as expected
Now I marked the osd in and wait until all stabilized. Then I set the crush weight to 0. ceph osd crush reweight osd.111 0. I thought this lowers the crush weight of the node so even less chances that PG's end up on an osd of the same node. However the result are
NR PG's OSD 1 61 1 83 1 86 3 108 4 109 5 110 2 112 5 113 7 114 5 115 2 116
except for 3 PG's all other PG's ended up on an osd belonging to the same node :-O. Is this expected behaviour? Can someone explain?? This is on nautilus 14.2.8.
Thanks
Marcel _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io
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