Hi Thomas,
How does your crush map/tree look?
If your crush failure domain is by host, then your 96x 8T disks will be as useful as
you're 1.6T disks, because smallest failure domain is your limiting factor.
So you can either redistribute your disks to be 16x8T+32x1.6T per host, or you could group
your 1.6T nodes into groups (chassis perhaps) and move the 8T nodes into their own
chassis, and then set your failure domain to chassis, and this would likely lead to a much
more even distribution.
I imagine right now you're 1.6T disks are nearful, and your 8T disks are anything
but.
Be careful with something like this however, because you will probably run into some iops
discrepancies due to number of spindles/TB difference across 'chassis'.
Hope that helps.
Reed
On Sep 23, 2019, at 4:07 AM, Thomas
<74cmonty(a)gmail.com> wrote:
Hi,
I'm facing several issues with my ceph cluster (2x MDS, 6x ODS).
Here I would like to focus on the issue with pgs backfill_toofull.
I assume this is related to the fact that the data distribution on my
OSDs is not balanced.
This is the current ceph status:
root@ld3955:~# ceph -s
cluster:
id: 6b1b5117-6e08-4843-93d6-2da3cf8a6bae
health: HEALTH_ERR
1 MDSs report slow metadata IOs
78 nearfull osd(s)
1 pool(s) nearfull
Reduced data availability: 2 pgs inactive, 2 pgs peering
Degraded data redundancy: 304136/153251211 objects degraded
(0.198%), 57 pgs degraded, 57 pgs undersized
Degraded data redundancy (low space): 265 pgs backfill_toofull
3 pools have too many placement groups
74 slow requests are blocked > 32 sec
80 stuck requests are blocked > 4096 sec
services:
mon: 3 daemons, quorum ld5505,ld5506,ld5507 (age 98m)
mgr: ld5505(active, since 3d), standbys: ld5506, ld5507
mds: pve_cephfs:1 {0=ld3976=up:active} 1 up:standby
osd: 368 osds: 368 up, 367 in; 302 remapped pgs
data:
pools: 5 pools, 8868 pgs
objects: 51.08M objects, 195 TiB
usage: 590 TiB used, 563 TiB / 1.1 PiB avail
pgs: 0.023% pgs not active
304136/153251211 objects degraded (0.198%)
1672190/153251211 objects misplaced (1.091%)
8564 active+clean
196 active+remapped+backfill_toofull
57 active+undersized+degraded+remapped+backfill_toofull
35 active+remapped+backfill_wait
12 active+remapped+backfill_wait+backfill_toofull
2 active+remapped+backfilling
2 peering
io:
recovery: 18 MiB/s, 4 objects/s
Currently I'm using 6 OSD nodes.
Node A
48x 1.6TB HDD
Node B
48x 1.6TB HDD
Node C
48x 1.6TB HDD
Node D
48x 1.6TB HDD
Node E
48x 7.2TB HDD
Node F
48x 7.2TB HDD
Question:
Is it advisable to distribute the drives equally over all nodes?
If yes, how should this be executed w/o ceph disruption?
Regards
Thomas
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