Hi, apparently, db_slots is still not implemented. I just tried it on a test cluster with 18.2.2: # ceph orch apply -i osd-slots.yaml --dry-run Error EINVAL: Failed to validate OSD spec "osd-hdd-ssd.db_devices": Filtering for `db_slots` is not supported If it was, I would be interested as well if it could be used in combination with block_db_size to not consume the entire disk. We haven't had too wild configuration requirements yet, I usually stick to block_db_size (without limit) if there's a requirement to not use the entire db disk. Because as you already stated, in that case the orchestrator creates one db device per HDD with the specified db size, leaving space on the db device. Maybe that's one of the reasons that db_slots still hasn't been implemented? Regards, Eugen Zitat von Robert Sander <r.sander@heinlein-support.de>:
Hi,
what is the purpose of the db_slots attribute in a DriveGroup specification?
My interpretation of the documentation is that I can define how many OSDs use one db device.
https://docs.ceph.com/en/reef/cephadm/services/osd/#additional-options
"db_slots - How many OSDs per DB device"
The default for the cephadm orchestrator is to create as many DB volumes on a DB device as needed for the number of OSDs.
In a scenario where there are empty slots for HDDs and an existing DB device should not be used fully "db_slots" could be used.
But even if db_slots is in an OSD service spec the orchestrator will only create as many DB volumes as there are HDDs currently available.
There is a discussion from 2021 where the use of "block_db_size" and "limit" is suggested: https://lists.ceph.io/hyperkitty/list/ceph-users@ceph.io/thread/6EVOYOHS3BTT...
Shouldn't db_slots make that easier?
Is this a bug in the orchestrator?
Regards -- Robert Sander Heinlein Consulting GmbH Schwedter Str. 8/9b, 10119 Berlin
http://www.heinlein-support.de
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