| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2019-03-14 | |||
| 13:15:42 | kashyap | mdbooth: What about also doing: s/writethrough/writeback/ for SMBFS and virtuozzo? | |
| 13:15:50 | kashyap | See: nova/virt/libvirt/volume/smbfs.py and nova/virt/libvirt/volume/vzstorage.py. | |
| 13:16:04 | mdbooth | kashyap: We should do that. | |
| 13:16:14 | mdbooth | kashyap: Separate patches though, please. | |
| 13:16:18 | kashyap | Yes! | |
| 13:16:22 | kashyap | That's what I noted in the TODO | |
| 13:16:27 | mdbooth | Also super-low priority, because likely nobody cares. | |
| 13:16:27 | kashyap | (In the commit) | |
| 13:16:36 | kashyap | [quote] | |
| 13:16:37 | kashyap | TODO: Investigate if this is okay for Cinder volume drivers such as SMBFS and Virtuozzo. If so, then change them to use 'writeback' as well (probably in separate patches). | |
| 13:16:40 | kashyap | [/quote] | |
| 13:16:52 | kashyap | mdbooth: Yes, nobody cares, except when it comes to bite you. | |
| 13:17:04 | kashyap | Might as well do it when I remember it; or else it goes into /dev/null of my brain | |
| 13:17:06 | mdbooth | kashyap: It would only bite you if you used those things. | |
| 13:17:24 | kashyap | (Yep.) | |
| 13:28:17 | openstackgerrit | Boxiang Zhu proposed openstack/nova master: Raise error when force_raw_images and images_type are incompatible https://review.openstack.org/640271 | |
| 13:34:45 | openstackgerrit | Boxiang Zhu proposed openstack/nova master: Remove unsafe convert of lvm imagebackend https://review.openstack.org/642667 | |
| 13:37:13 | zhubx007 | mdbooth: looking forward to your review on two patches ^ thanks :) | |
| 13:45:03 | mriedem | dansmith: can i get your +2 back on https://review.openstack.org/#/c/643151/ - i had to fix a test otherwise it's the same | |
| 13:45:21 | dansmith | mriedem: well, the test failed in a weird way in functional, | |
| 13:45:30 | dansmith | so I was waiting to see how the recheck turned out | |
| 13:45:38 | mriedem | that's the infra changes | |
| 13:45:39 | mriedem | but ok | |
| 13:45:51 | mriedem | this https://review.openstack.org/#/c/643129/ | |
| 13:45:52 | dansmith | I looked in the log and couldn't see anything actually broken | |
| 13:46:00 | mriedem | it was this https://review.openstack.org/#/c/643129/4/.zuul.yaml | |
| 13:46:04 | mriedem | broke everything over night | |
| 13:46:18 | dansmith | okay... and the result is it just doesn't even run? | |
| 13:46:36 | mriedem | the old func py35 job couldn't find the py35 interpreter | |
| 13:46:47 | mriedem | with the new job parent it should be setup for that | |
| 13:46:54 | mriedem | uses a xenial rather than bionic node | |
| 13:47:08 | dansmith | okay I didn't see anything about that in the log, but that's fine, just sayin' I was looking at it already this morning and that's why I didn't just slap back on there | |
| 13:47:13 | dansmith | but if it's known | |
| 13:47:14 | dansmith | .. | |
| 13:47:37 | mriedem | thanks | |
| 13:52:21 | mriedem | frickler: looks like you fixed that ceph thing https://review.openstack.org/#/c/643150/ | |
| 13:53:14 | openstackgerrit | Eric Fried proposed openstack/nova master: WIP/PoC: Bypass ironicclient for node.get https://review.openstack.org/642899 | |
| 14:10:56 | openstackgerrit | Matt Riedemann proposed openstack/nova master: Re-enable Ceph in live migration testing https://review.openstack.org/643150 | |
| 14:10:57 | openstackgerrit | Matt Riedemann proposed openstack/nova master: Customize irrelevant-files for nova-live-migration job https://review.openstack.org/643346 | |
| 14:18:51 | openstackgerrit | Elod Illes proposed openstack/nova stable/ocata: Use ubuntu-xenial for sphinx jobs https://review.openstack.org/643320 | |
| 14:40:57 | dansmith | is jaypipes just never around anymore? | |
| 14:46:40 | cdent | dansmith: I _think_ he's travelling this week. Not sure if it was business or pleasure. | |
| 14:46:48 | dansmith | oh okay | |
| 14:47:09 | cdent | he was at least on a plane on monday | |
| 15:41:22 | kashyap | aspiers: When you're about, refer to comment#11 here: https://review.openstack.org/#/c/633855/11 | |
| 15:47:42 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: qemu: Make disk image conversion dramatically faster https://review.openstack.org/640781 | |
| 15:47:43 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: Use 'writeback' QEMU cache mode for Nova instances https://review.openstack.org/641981 | |
| 15:47:43 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: vzstorage: Use 'writeback' QEMU cache mode https://review.openstack.org/643376 | |
| 15:47:44 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: smbfs: Use 'writeback' QEMU cache mode https://review.openstack.org/643377 | |
| 15:54:42 | cdent | I | |
| 15:57:57 | edleafe | cdent: Roman numerals, anyone? | |
| 16:00:05 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: vzstorage: Use 'writeback' QEMU cache mode https://review.openstack.org/643376 | |
| 16:00:06 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: smbfs: Use 'writeback' QEMU cache mode https://review.openstack.org/643377 | |
| 16:00:28 | kashyap | Some simple catch above, if anyone wants a change of scenery. | |
| 16:00:47 | kashyap | (The core change and documentation is in: libvirt: Use 'writeback' QEMU cache mode for Nova instances https://review.openstack.org/641981) | |
| 16:02:14 | cdent | edleafe: α ω | |
| 16:02:57 | edleafe | cdent: make up your mind: greek or roman?? | |
| 16:04:48 | cfriesen | kashyap: quick question. did you try running a "sync" after the writeback image conversion test to ensure the data had actually hit the disk? | |
| 16:05:17 | cfriesen | or do we even care if it did or not? | |
| 16:05:49 | kashyap | cfriesen: No, I didn't do. But, 'sync' is not required at all in this case -- why? | |
| 16:06:59 | cfriesen | well, your numbers look a lot like it just wrote to the cache. If the host crashes at that point, it might think it has valid data on-disk but actually have a corrupt image. | |
| 16:09:35 | cfriesen | now this may not actually be a problem in practice, just thought I'd raise it. | |
| 16:11:10 | kashyap | cfriesen: I got dropped off my IRC proxy; what was the last message you got from me? | |
| 16:11:31 | kashyap | (And if you wrote anything else after your "quick question ...", please re-post) | |
| 16:12:35 | cfriesen | I just said... your numbers look a lot like it just wrote to the cache. If the host crashes at that point, it might think it has valid data on-disk but actually have a corrupt image. Now this might not be a problem in practice, but I thought I'd mention it. | |
| 16:14:08 | kashyap | cfriesen: Noted, but ... I spent careful 4 days talking to QEMU Block Layer maint folks. | |
| 16:14:18 | kashyap | And not sure if my messages got through: | |
| 16:14:18 | kashyap | 17:05 < kashyap> cfriesen: No, I didn't do. But, 'sync' is not required at all in this case -- why? | |
| 16:14:21 | kashyap | 17:06 < kashyap> cfriesen: After image conversion completes successfully, QEMU issues fsync(), thus flushing the content down to disk. | |
| 16:14:38 | kashyap | cfriesen: So, the numbers are correct, FWIW. The data _is_ on disk. | |
| 16:15:05 | kashyap | cfriesen: I even audited QEMU's code (with call trac) to track down 'qemu-img convert' ends up calling fsync(). | |
| 16:15:35 | kashyap | cfriesen: There is the call trace (since I sometimes see you pop into #qemu on OFTC :-)) -- https://kashyapc.fedorapeople.org/qemu-img-call-trace-to-fsync.txt | |
| 16:16:13 | kashyap | dansmith: Hehe, saw your "church retreat" remark on the channel archives (my IRC proxy kicked me, thanks to the IDENTIFY) | |
| 16:16:30 | kashyap | (I commented on that weshay asked) | |
| 16:16:34 | kashyap | s/on that/on that review/ | |
| 16:20:51 | cfriesen | kashyap: I just did an strace of qemu-img convert, and I see it calling fdatasync() rather than fsync(). But that should still be sufficient. | |
| 16:21:28 | kashyap | Yes, if fdatasync() is available it is used, otherwise its cousin fsync() | |
| 16:21:46 | kashyap | See the QEMU function call trace I posted earlier :-) | |
| 16:21:59 | kashyap | cfriesen: Shall I respin for the s/multiple orders/multiple times/? | |
| 16:23:03 | cfriesen | I did make it a nit. :) | |
| 16:24:42 | kashyap | cfriesen: Saw that; that's what I was referring to | |
| 16:25:00 | cfriesen | I mean, if I really thought it required a respin I'd have done -1 | |
| 16:25:25 | cfriesen | but if you're respinning for any other reason you could fix that up too | |
| 16:27:01 | cfriesen | do we need four separate commits for this? I mean, if we make the change one place it makes sense to make it everywhere, right? | |
| 16:28:01 | cfriesen | I've gotten flack for too-big patches though, so maybe my opinion is biased. :) | |
| 16:31:56 | kashyap | cfriesen: See the discussion in the scrollback here in the channel with mdbooth (who asked for separte patches) | |
| 16:32:12 | kashyap | Because: each one is touching a completely different driver (SMBFS vs. Virtuozzo, etc) | |
| 16:32:32 | kashyap | (It is the "one logical change per patch" rule.) | |
| 16:33:06 | mdbooth | cfriesen: Just MHO, but the potential for fallout and therefore reverts seems slightly different in each case. | |
| 16:33:22 | cfriesen | okay, works for me. | |
| 16:33:44 | mdbooth | But they all definitely have the same theme. | |
| 16:34:27 | mdbooth | cfriesen: And we can't test virtuozzo | |
| 16:34:38 | kashyap | Exactly, the "potential for reverts" is the thing | |
| 16:35:25 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: qemu: Make disk image conversion dramatically faster https://review.openstack.org/640781 | |
| 16:35:25 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: Use 'writeback' QEMU cache mode for Nova instances https://review.openstack.org/641981 | |
| 16:35:26 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: vzstorage: Use 'writeback' QEMU cache mode https://review.openstack.org/643376 | |
| 16:35:26 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: smbfs: Use 'writeback' QEMU cache mode https://review.openstack.org/643377 | |
| 16:35:34 | kashyap | cfriesen: ^ Mind re-acking? | |
| 16:36:16 | openstackgerrit | Eric Fried proposed openstack/nova master: WIP/PoC: Bypass ironicclient for node.get https://review.openstack.org/642899 | |
| 16:37:42 | cfriesen | I suspect the biggest impact will be I/O usage patterns on the host, since now we'll be queueing up a bunch of writes and flushing them all at once. | |