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#openstack-nova - 2020-07-24
16:17:58 sean-k-mooney i filestore used to be the default before
16:18:14 dansmith okay that's what I was saying
16:18:36 dansmith I still don't get where the 10G comes from, other than that something is clearly different with blue vs xfs stores
16:18:46 sean-k-mooney bluestore has been the default for a few releases now. filestore is deprecated upstream and downstream in ops
16:19:06 sean-k-mooney dansmith: i think that is the default size that the ceph tool uses
16:19:19 sean-k-mooney when its creating a backing file
16:19:36 dansmith okay I don't see that anywhere
16:20:19 sean-k-mooney its being created by the ceph osd itself here https://zuul.opendev.org/t/openstack/build/13d8a055ff1b4be0b627205f4d51d50f/log/controller/logs/ceph/ceph-osd.0_log.txt#4
16:20:26 dansmith I imagine that keeping the loopback mount for var lib ceph is ideal for the plugin as long as we have stable branches that use that
16:20:38 dansmith sean-k-mooney: yeah I get that :)
16:20:50 dansmith sean-k-mooney: I'm saying I don't know where 10G is set or assumed or whatever ;)
16:21:00 sean-k-mooney yes we can proably change that in the job?
16:21:07 melwitt dansmith: is it not here? https://zuul.opendev.org/t/openstack/build/13d8a055ff1b4be0b627205f4d51d50f/log/controller/logs/ceph/ceph-osd.0_log.txt#18
16:21:24 dansmith lol
16:21:28 dansmith yes, I understand 10G is being used
16:21:34 sean-k-mooney or if the destack pluging is branched we can change it only on the branchs that use nautilus
16:21:35 dansmith I'm saying I don't see a config for that
16:21:54 dansmith https://docs.ceph.com/docs/mimic/rados/configuration/bluestore-config-ref/
16:21:58 sean-k-mooney if there is a config it would be the ceph config file
16:22:03 melwitt oh, sorry, just saying that's a command that is setting 10G deliberately
16:22:28 dansmith melwitt: yep I think that's understood now
16:22:28 melwitt from what sean-k-mooney was saying, I thought no one saw a deliberate setting of it yet
16:22:41 melwitt that it was happening "automatically"
16:22:58 melwitt I am caught up now
16:23:16 dansmith all I'm saying is, I imagine that bluestore can have more than 10G of backing store, and if it's not basing that on actual disk free space, it's probably a config somewhere or something :)
16:23:51 melwitt yeah, I understand now
16:24:09 melwitt I misunderstood what sean was saying earlier
16:25:22 dansmith the bluestore config actually seems to be mostly focused on using physical devices
16:27:12 sean-k-mooney melwitt: it happens frequently that people missunderstad me. well not that often if i type what i ment to type but i am bad at not doing that
16:28:56 melwitt sean-k-mooney: eh, I often have trouble understanding people so by our powers combined... !
16:30:46 dansmith I HAVE NO IDEA WHAT YOU PEOPLE ARE SAYING
16:31:09 melwitt I AM GOOD AT DEALING WITH PEOPLE
16:31:47 sean-k-mooney stephenfin: talking about storage does this to people
16:32:16 sean-k-mooney just taking a step back
16:32:30 sean-k-mooney we are happy we know where the 10G size is comming from now
16:32:36 melwitt StOrAGE
16:33:10 sean-k-mooney and that we are proably just hitting a real no valid host error because we are actully providing 10G to cpeh instead of 24
16:33:28 sean-k-mooney so the ceph jobs failrues are not related to dansmith's recent changes to the job
16:33:35 sean-k-mooney yes?
16:34:10 dansmith sean-k-mooney: yeah I thought we were assuming that
16:34:16 dansmith because it's clearly just placement
16:34:31 dansmith my job might be slower (or faster) causing us to hit it more than we were or something
16:35:05 sean-k-mooney so we just either a.) swap back to file store to get the old behavior or b.) mount our loopback file in such a way that the bluestore block device uses our 24G loopback device instead of creating its own
16:35:29 dansmith yeah so I figured going back to xfs would be ideal for compatibility with everything
16:35:38 dansmith my system clearly gets xfs
16:35:51 dansmith I assume the workers are getting blue because they're newer ubuntu or something
16:36:00 dansmith I'm still on bionic
16:36:01 sean-k-mooney dansmith: sure but eventurally we will have to move since i think filestore is deprected in ceph
16:36:05 dansmith sure
16:36:16 dansmith pain now or pain later
16:36:21 dansmith pain later might be someone else's pain :P
16:36:52 sean-k-mooney so i guess what we are looking for is a ceph config option to select filestore for the osd backend
16:37:43 sean-k-mooney that or we set it on the osd create command
16:38:02 dansmith yeah
16:38:37 sean-k-mooney so this code https://github.com/openstack/devstack-plugin-ceph/blob/master/devstack/lib/ceph#L475-L484
16:39:03 sean-k-mooney that inital sudo ceph -c ${CEPH_CONF_FILE} osd create
16:39:06 dansmith well, the other option is to figure out how to make blue use 20ish G instead of 10,
16:39:20 dansmith which would be less impactful than retooling the mount stuff in the ceph plugin
16:40:00 sean-k-mooney well we are mounting it on /var/lib/ceph
16:40:08 sean-k-mooney so i guess this is already plugin specific
16:40:24 sean-k-mooney we are likely resuing the same function that is used for cinder and just passing the mount path
16:40:57 sean-k-mooney ya we are just calling create_disk https://github.com/openstack/devstack-plugin-ceph/blob/master/devstack/lib/ceph#L387
16:41:01 dansmith cinder just wants a loop not a mounted fs though right/
16:41:52 sean-k-mooney maybe this is the fucntion in devstack https://github.com/openstack/devstack/blob/eee60c76719c02c08dba7b7fb703798a056b22b9/functions#L758-L789
16:42:19 sean-k-mooney that kind of looks like a hack
16:42:41 sean-k-mooney e.g. that does not look like it was created orginally for ceph
16:43:26 melwitt hm, I found this https://forum.proxmox.com/threads/proxmox-ceph-osd-partition-created-with-only-10gb.55291/
16:43:31 sean-k-mooney oh its for swift orginially
16:46:20 sean-k-mooney i think the "sudo ceph-osd -c ${CEPH_CONF_FILE} -i ${OSD_ID} --mkfs" is the one we would need to modify
16:49:32 sean-k-mooney melwitt: that does seam like the same issue more or less
16:49:48 melwitt yeah, I'm having trouble understanding it
16:50:50 melwitt the last comment links to another post https://forum.proxmox.com/threads/where-can-i-tune-journal-size-of-ceph-bluestore.44000/ where they're talking about tuning journal size and bluestore_block_db_size and bluestore_block_wal_size
16:51:02 melwitt and I don't know what any of that is or means
16:51:22 melwitt (in ceph.conf)
17:01:31 sean-k-mooney those are not realated to the data storage size of the osd
17:01:55 sean-k-mooney blustore has an embeed database that track where the logic block are located on disk
17:02:27 sean-k-mooney wal i think it the write ahead log or somethingl like that
17:02:39 sean-k-mooney its part of how it does write journalling
17:03:02 sean-k-mooney in both cases they are turning parmatner for how bluestore can save its metadata
17:03:56 sean-k-mooney unlike file sotre it can save it inline in the blockdevice it is managening or it can save it oh external devices and they support tuneing of the sizing of them independelty
17:04:33 openstackgerrit Artom Lifshitz proposed openstack/nova master: Handle Neutron errors in _post_live_migration() https://review.opendev.org/729763
17:09:57 melwitt sean-k-mooney: found a new thing https://bugzilla.redhat.com/show_bug.cgi?id=1597048
17:09:57 openstack bugzilla.redhat.com bug 1597048 in RADOS "ceph osd df not showing correct disk size and causing cluster to go to full state" [High,Closed: notabug] - Assigned to bhubbard
17:10:59 dansmith imagine that :)
17:11:24 melwitt what
17:11:27 sean-k-mooney it should be 3.7TB but is 10G
17:11:41 dansmith melwitt: "not showing correct disk size"
17:11:57 melwitt yeah?
17:12:14 melwitt I'm still googling for why bluestore is maxed out at 10G
17:12:17 dansmith melwitt: just saying, I think we've stumbled into a realization that our df reporting on ceph in libvirt es no bueno right?
17:12:23 melwitt no
17:13:08 dansmith oh did I miss something? I thought those RHN articles were indicating that we're reporting the wrong thing still
17:13:51 sean-k-mooney https://bugzilla.redhat.com/show_bug.cgi?id=1597048#c8
17:13:51 openstack bugzilla.redhat.com bug 1597048 in RADOS "ceph osd df not showing correct disk size and causing cluster to go to full state" [High,Closed: notabug] - Assigned to bhubbard
17:14:08 dansmith like, if we're reporting the total size of the osd, but that's shared by vms and images, we'll be telling placement it can allocate all that space for instances but it can't
17:14:20 sean-k-mooney so it look like they hever actully got to the root cause of why the bluestore file was a 10G file
17:14:37 sean-k-mooney they just redeployed with file store an ignored it
17:15:01 melwitt yeah.. but then what does this mean? "The BlueStore block device was a file named with a block, not a symlink to block device partition of this disk and that file size was 10G hence it was showing the size of the OSD as 10G."
17:15:24 sean-k-mooney i think they ment
17:15:45 sean-k-mooney that in stead of it being a symlink to /dev/sdX

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