| === shardy_afk is now known as shardy | ||
| Odd_Bloke | smoser: I'm looking at switching MBR disk setup to use sectors (rather than MB), because sfdisk in wily has dropped support for units other than sectors. | 14:10 |
|---|---|---|
| smoser | yes please. | 14:11 |
| Odd_Bloke | smoser: How would you suggest I test this? I've done [33, [66, 82]], which is the canonical example we use. | 14:11 |
| Odd_Bloke | But I don't really know what corner cases we might have that I should look at. | 14:11 |
| smoser | mainly i think you dont have to care. | 14:11 |
| smoser | CHS is garbage. | 14:11 |
| smoser | thats waht you're asking about, right? | 14:12 |
| smoser | what did '33, 66, 82' mean ? | 14:12 |
| Odd_Bloke | smoser: No, at the moment we do (essentially) 'cat <list of partitions> | sfdisk -uM <device>'. | 14:13 |
| Odd_Bloke | smoser: But sfdisk no longer supports megabytes as units, so I'm switching to using sectors as the units. | 14:13 |
| Odd_Bloke | smoser: This is https://bugs.launchpad.net/cloud-init/+bug/1460715 | 14:13 |
| smoser | ah. ok. | 14:14 |
| smoser | what did you mean 33, 66, 82 ? | 14:14 |
| Odd_Bloke | smoser: So I've tested using 'layout: [33, [66, 82]' (i.e. one-third ext4, two-thirds swap), but I don't really know what else to try to check that it works in practice. | 14:14 |
| smoser | Odd_Bloke, ok. now reading code and understand more. | 14:19 |
| smoser | well you basically have to turn everything into sectors. | 14:20 |
| smoser | now, to deal with sfdisk | 14:20 |
| Odd_Bloke | smoser: Yeah, it's actually surprisingly painless. | 14:21 |
| Odd_Bloke | smoser: I've got a branch prepped, I'm just trying to test it before pushing it up for review. | 14:21 |
| smoser | i've never really used that code. | 14:21 |
| smoser | in the future the plan is to support the disk layout settings taht curtin can do. | 14:22 |
| Odd_Bloke | smoser: OK, I'll just push this up for review then. | 14:22 |
| Odd_Bloke | I've done some basic testing. | 14:22 |
| Odd_Bloke | smoser: That's https://code.launchpad.net/~daniel-thewatkins/cloud-init/lp1460715/+merge/274897 | 14:40 |
| smoser | Odd_Bloke, it'd be good to know if this code runs on old sfdisk | 14:41 |
| Odd_Bloke | smoser: Ah, good point. | 14:42 |
| Odd_Bloke | smoser: The existing trusty code doesn't work even without my changes. /o\ | 14:55 |
| Odd_Bloke | Ah, I'm hitting https://bugs.launchpad.net/cloud-init/+bug/1311463. | 14:56 |
| smoser | Odd_Bloke, added a review | 14:59 |
| Odd_Bloke | smoser: Thanks! Replied to the inline comment. | 15:06 |
| smoser | i've always been confused by sfdisk also | 15:07 |
| smoser | lets find the real ansewr. | 15:08 |
| smoser | but i suspect it is 512 | 15:08 |
| Odd_Bloke | smoser: I've been poking around in that code; let me have a dig before you switch to this. | 15:09 |
| Odd_Bloke | (As in, I've been poking in the sfdisk code) | 15:09 |
| smoser | reading http://karelzak.blogspot.com/2014/10/new-sfdisk.html | 15:10 |
| Odd_Bloke | smoser: So my code doesn't backport to trusty nicely, because old 'sfdisk -l' output is different. | 15:12 |
| smoser | yeah. i'm aware of such pain . | 15:13 |
| smoser | from growpart | 15:13 |
| smoser | it does support both. but its a pita | 15:13 |
| smoser | http://bazaar.launchpad.net/~cloud-utils-dev/cloud-utils/trunk/view/head:/bin/growpart | 15:14 |
| smoser | Odd_Bloke, the thing is that if we update to only supporting new, then anyone who picks this up is busted on old sfdisk | 15:14 |
| smoser | in growpart, SFDISK_VERSION madness. | 15:15 |
| Odd_Bloke | smoser: ;.; | 15:16 |
| Odd_Bloke | smoser: So libfdisk definitely supports variable sector sizes; I don't know if we'd ever see them in practice. | 15:19 |
| smoser | but then its not clear to me if it woudl be used anyway. | 15:20 |
| smoser | logical sector size versus physical sector size | 15:20 |
| Odd_Bloke | smoser: Right. | 15:22 |
| Odd_Bloke | smoser: I have a meeting coming up, but I'll pick this up after that. | 15:22 |
| smoser | Odd_Bloke, so. | 16:56 |
| smoser | through some experimentation, i can verify that sfdisk uses 512 byte sectors | 16:56 |
| === mfisch` is now known as mfisch | ||
| Odd_Bloke | smoser: You're sure we won't hit funky hardware somewhere where it doesn't? | 16:59 |
| === mfisch is now known as Guest27947 | ||
| smoser | i dont think so | 16:59 |
| smoser | http://paste.ubuntu.com/12863364/ | 16:59 |
| === Guest27947 is now known as mfisch | ||
| smoser | Odd_Bloke, ^ that boots a guest with 4096 physical size and 512 logical (interestingly, it wont boot if you set logical to 4096). | 17:00 |
| smoser | verified that the kernel says my physical size is 4096 | 17:01 |
| smoser | and that size reported (in your 'sfdisk --list') is in 512 | 17:01 |
| smoser | Odd_Bloke, http://paste.ubuntu.com/12863544/ | 17:12 |
| harlowja | smoser https://github.com/openstack/cloud-init | 17:16 |
| harlowja | guess now cloud-init == openstack | 17:16 |
| harlowja | lol | 17:16 |
| harlowja | Odd_Bloke ^ claudiupopa | 17:17 |
| smoser | oh well. it is. as it is. | 17:17 |
| harlowja | :-P | 17:17 |
| natorious | oh wow | 17:17 |
| natorious | did they merge the stackforge org into openstack? | 17:17 |
| natorious | I suppose | 17:17 |
| harlowja | yup | 17:17 |
| harlowja | stackforge gone... | 17:17 |
| harlowja | and/or retired | 17:18 |
| natorious | fwiw, I report cloud-init hours worked as openstack dev hours | 17:18 |
| harlowja | nice | 17:18 |
| harlowja | well now u can do that without feeling bad, ha | 17:18 |
| natorious | lol, no bad feelings here :P | 17:19 |
| Odd_Bloke | smoser: So looking at the util-linux code; sector size defaults to 512, but it does do an 'ioctl(fd, BLKSSZGET, sector_size)' call to actually query the device (https://git.kernel.org/cgit/utils/util-linux/util-linux.git/tree/lib/blkdev.c#n193). | 17:19 |
| Odd_Bloke | smoser: But that does mean that a `blockdev --getss $DEVICE` is definitely going to return the same answer, which would save on parsing sfdisk output. | 17:20 |
| Odd_Bloke | Let me check that makes sense on trusty. | 17:21 |
| smoser | ok. i'm wrong | 17:50 |
| smoser | http://paste.ubuntu.com/12864078/ | 17:50 |
| smoser | your'e right about blockdev --getss | 17:51 |
| smoser | but i think thats the same as woudl be returned by *logical* | 17:51 |
| smoser | http://paste.ubuntu.com/12864114/ | 17:52 |
| smoser | ^-- | 17:52 |
| smoser | so reading logical in sys shoudl give you what sfdisk does. | 17:53 |
| smoser | i managed to create a device with 4096 logical | 17:53 |
| smoser | so ... sfdisk uses logical sectors. not physical sectors. | 17:54 |
| === shardy is now known as shardy_afk | ||
| === Guest3686 is now known as mgagne | ||
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