| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2019-03-21 | |||
| 09:55:48 | bauzas | if operators don't want to expect modern OSes, it's their choices | |
| 09:55:51 | mdbooth | bauzas: I saw that. Honestly, though, this hasn't been an issue for at least a decade, maybe 2. | |
| 09:56:11 | bauzas | mdbooth: not really, you can enable caching on some OSes that don't flush, right? | |
| 09:56:13 | mdbooth | I think it just increases cognitive load on the reader for no practical benefit. | |
| 09:56:28 | bauzas | from my recall, W2K is one of those | |
| 09:56:28 | sean-k-mooney | mdbooth: there are still people running centos 5 | |
| 09:56:41 | mdbooth | sean-k-mooney: Centos 5 definitely flushes! | |
| 09:56:42 | sean-k-mooney | mdbooth: didnt it have issue with flushing | |
| 09:56:45 | sean-k-mooney | ok | |
| 09:57:16 | sean-k-mooney | that was the distro that i always worried about for this kind of thing | |
| 09:57:33 | mdbooth | If your OS doesn't flush data on request, you're going to find out about that real soon. | |
| 09:58:06 | sean-k-mooney | i know it does not partcally like virtio disks as i useulaly had to revert to useing other disk bus like ide to avoid kernel issues | |
| 09:58:32 | mdbooth | I remember having to be very careful shutting down my old 286-clone Tandy running DOS, though. | |
| 09:58:56 | bauzas | oh, I remember some PITAs I got with Win2K guests in the past with OpenStack Essex | |
| 09:59:03 | bauzas | I'm pretty sure they weren't flushing | |
| 09:59:23 | sean-k-mooney | im sure that at least 50% of all openstack workloads :P | |
| 09:59:26 | bauzas | but this could have been fixed in a SP or something else | |
| 09:59:35 | sean-k-mooney | dos gaming in the cloud | |
| 10:00:12 | bauzas | actually, that's a good question now we have containerizing OSes like Atomic | |
| 10:00:25 | bauzas | do we still flush on disk ? | |
| 10:00:40 | sean-k-mooney | with containers? | |
| 10:00:45 | sean-k-mooney | that shoudl not change | |
| 10:01:03 | mdbooth | bauzas: It's really an application issue: your application needs to flush. | |
| 10:01:23 | mdbooth | If the application flushes, the OS should also flush. | |
| 10:01:53 | mdbooth | The only thing writeback vs writethrough is going to fix is if your application flushes but the OS does not. | |
| 10:02:32 | mdbooth | If the application doesn't flush, the OS can't flush it anyway, as it may not have the data. | |
| 10:03:57 | bauzas | hum, reading https://lifehacker.com/do-i-really-need-to-eject-usb-drives-before-removing-th-5863810 | |
| 10:04:08 | bauzas | man, why is this so complicated ? | |
| 10:04:31 | bauzas | anyway, I agree, it's maybe just a strawman | |
| 10:04:43 | bauzas | but I still feel we need to explain it | |
| 10:05:10 | mdbooth | bauzas: USB drives don't need O_SYNC either if your application flushes and you wait for your application to finish before unplugging. | |
| 10:05:44 | mdbooth | Eject flushes the whole disk. | |
| 10:08:43 | bauzas | yeah, just reading http://msdn.microsoft.com/en-us/library/windows/desktop/aa364218%28v=vs.85%29.aspx | |
| 10:08:56 | bauzas | anyway, I'm balanced | |
| 10:09:21 | bauzas | see, we're talking for 30 mins about something needing more than just a glance | |
| 10:09:41 | bauzas | the fact that mdbooth and kashyap know the situation makes reasonable the change | |
| 10:09:58 | bauzas | but I just feel we need to capture this knowledge | |
| 10:10:08 | bauzas | and explain it thru the relnote | |
| 10:34:37 | stephenfin | gibi: Looks like you solved it :) | |
| 10:35:03 | gibi | stephenfin: yeah, I managed. | |
| 10:51:56 | sean-k-mooney | bauzas: for the record we can talk for 30 mins about just about any topic :) | |
| 11:41:39 | kashyap | bauzas: Just back; ah, I mistook your formatting comment | |
| 11:52:12 | openstackgerrit | Balazs Gibizer proposed openstack/nova master: Fix links to neutron QoS minimum bandwidth doc https://review.openstack.org/645084 | |
| 12:01:03 | kashyap | sean-k-mooney: CentOS-5 is perfectly fine w.r.t. flushes. Again, as noted only *horribly* old OSes that don't matter (like RHEL-4 or even older versions of Windoze) | |
| 12:01:21 | kashyap | ... that had problems. And they're not relevant. | |
| 12:02:00 | sean-k-mooney | kashyap: ya | |
| 12:02:17 | kashyap | sean-k-mooney: /me reworks the rel note; and you're right - some of the info I could add there | |
| 12:02:30 | kashyap | But as Matt noted, I was being careful of not adding needless cognitive load to the reader. | |
| 12:02:49 | sean-k-mooney | i just have had data curption issue with centos 5 and centos 5 based vnf in the past and was not sure if that was due to flushing | |
| 12:05:20 | sean-k-mooney | that said it could equally have been down to the use of ext2/3? i cant rememebr but all i recal was we had to be very care to ensure we shutdown cleanly or we woudl have to do a rebuild with a clean image and/or do a rescue to fix the file system | |
| 12:15:10 | kashyap | sean-k-mooney: bauzas: Before I upload, does this read better? -- https://kashyapc.fedorapeople.org/PS14-writeback-cache-mode-for-guests-a7e4d2806c956164.yaml.txt | |
| 12:15:13 | kashyap | mdbooth: ^ | |
| 12:17:25 | kashyap | (Hit refresh, if you already clicked it :D) | |
| 12:17:49 | sean-k-mooney | haha i had | |
| 12:18:25 | kashyap | Sorry, removed a duplication. (/me is obsessed with words) | |
| 12:19:00 | sean-k-mooney | you also just fixed an issue i ws goint to raise | |
| 12:19:31 | sean-k-mooney | we are not ment to use phases like "we're" | |
| 12:19:33 | kashyap | Which one? | |
| 12:19:42 | kashyap | Yeah, I know. Contractions, etc. | |
| 12:20:14 | kashyap | I find it a bit irritating, though. I'd assume people (even non-native speakers) are competent enough to parse "we're" as "we are" | |
| 12:20:29 | kashyap | But I see where "I'd" can can confusion, as it can read: "I had", or "I would" :D | |
| 12:20:33 | sean-k-mooney | actully its not the contractrions | |
| 12:20:52 | kashyap | Oh? | |
| 12:21:25 | sean-k-mooney | we are ment to say nova in its the wrong perspective | |
| 12:23:18 | kashyap | tox -e releasenotes | |
| 12:23:19 | sean-k-mooney | https://docs.openstack.org/doc-contrib-guide/writing-style/general-writing-guidelines.html#write-in-second-person | |
| 12:23:23 | kashyap | Err, wrong window | |
| 12:24:19 | sean-k-mooney | "Use first person plural pronouns (we, our) judiciously." we are allowed to use "we" in some cases but its generally not teh perfered pharsing | |
| 12:24:22 | kashyap | Right, I normally avoid using "we", beceause it is so loaded | |
| 12:24:29 | kashyap | Thanks for the pointer, though :-) | |
| 12:25:09 | sean-k-mooney | kashyap: am so to your origninal question i would remove "And OSes do that." | |
| 12:25:54 | sean-k-mooney | i dont think its needed but otherswise that looks ok | |
| 12:26:03 | kashyap | sean-k-mooney: Not quite sure, otherwise it leaves the reader in the dark. They'll wonder: "will the OS do or not". But all OSes "that matter" do that | |
| 12:26:42 | sean-k-mooney | perhaps | |
| 12:27:11 | kashyap | I'll say "all modern OSes" | |
| 12:28:01 | sean-k-mooney | ya that read better how about "All modern OSes flush data as requried." | |
| 12:28:41 | sean-k-mooney | "And OSes do that." i a sentence fragment which is why i originly suggested removing it | |
| 12:28:55 | kashyap | It follows the previous sentence :-) But point noted. | |
| 12:28:58 | kashyap | I'll do that quick lunch | |
| 12:29:59 | sean-k-mooney | yes which is what makes it a sentence fragment :) it only makes sense when read in the context of the previous sentence. when read in isolate what does "that" refer to :) | |
| 12:30:13 | sean-k-mooney | anyway enjoy lunch | |
| 12:30:49 | kashyap | Okido, will join them :-) I'm all for clarity | |
| 12:57:29 | mriedem | bauzas: want to help get this in for queens? https://review.openstack.org/#/c/611945/ | |
| 13:08:24 | bauzas | mriedem: done | |
| 13:09:55 | mriedem | thanks | |
| 13:18:50 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: Use 'writeback' QEMU cache mode when 'none' is not viable https://review.openstack.org/641981 | |
| 13:18:51 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: smbfs: Use 'writeback' QEMU cache mode https://review.openstack.org/643377 | |
| 13:18:51 | openstackgerrit | Kashyap Chamarthy proposed openstack/nova master: libvirt: vzstorage: Use 'writeback' QEMU cache mode https://review.openstack.org/643376 | |
| 13:31:08 | openstackgerrit | Matt Riedemann proposed openstack/nova-specs master: Re-propose cross-cell-resize spec for Train https://review.openstack.org/642807 | |
| 13:31:24 | mriedem | dansmith: i tried to wordsmith the personality files limitation in the re-proposed cross-cell resize spec ^ | |
| 13:32:41 | dansmith | okay I guess I'll have to diff it to see the changed part | |
| 13:35:46 | sean-k-mooney | mriedem: were we recreating the config dirve during a cross cell migration or something that would cause issue for personality files? | |
| 13:36:34 | mriedem | we are | |
| 13:37:21 | mriedem | we spawn https://review.openstack.org/#/c/635080/13/nova/compute/manager.py@5145 | |
| 13:38:21 | sean-k-mooney | ok then back to the conversation we had yesterday. if its oke to do it for cross cell resize it logically means we may be able to do the same in general. perhaps contoled by a config option to addes klindgren concers regarding ssh keys ans scp | |
| 13:38:30 | cdent | scanning across the big window and seeing "mriedem: we spawn" is chilling and worrying. Somewhere in the basement the alien mriedem's are laying eggs | |
| 13:38:57 | mriedem | muwahaha | |
| 13:39:08 | mriedem | don't worry, i only harvest their organs | |
| 13:40:46 | mriedem | sean-k-mooney: i'm not necessarily saying it's ok, but i don't have a good solution right now for dealing with those during a cross-cell resize | |
| 13:41:08 | mriedem | without glance or nova-compute running it's own http server... | |