Discussion:
Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting
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David C. Rankin
2018-03-11 20:28:47 UTC
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All,

I experienced a hard lockup during kernel update to 4.15.8 on a Supermicro
Dual Opteron Quad-core box. I've updated this box 50 times without issue, but
something caused a hardlock. The filesystems are on mdadm linux-raid 1 partitions.

The hardlock occurred after the packages were installed and it was in
postprocessing at:

( 3/16) Install DKMS modules

Now on boot I receive:

Warning: /lib/modules/4.15.8-1-ARCH/modules.devname not found - ignoring
starting version 237
ERROR: devide `UUID=c7492ac0-e805...` not found. Skipping fsck.
mount: /new_root: can't find UUID UUID=c7492ac0-e805...
You are being dropped into an emergency shell.
sh: can't access tty; job control turned off
[rootfs ]#

(and the box hardlocks)

So I downloaded the 201803 iso to try and fix the box. I have to boot from
CD, since this box does not boot from USB. So I burn the .iso to CD (making
sure the CD Label is `ARCH_201803`) and boot the box again in attempt to fix it:

All goes well until...

:: Mounting '/dev/disk/by-label/ARCH_201803' to '/run/archiso/bootmnt'
Waiting 30 seconds for device /dev/disk/by-label/ARCH_201803 ...
ERROR: '/dev/disk/by-label/ARCH_201803' device did not show up after 30
seconds ...
Falling back to interactive prompt
You can try to fix the problem manually, log out when you are finished
sh: can't access tty; job control tuned off
[rootfs ]#

(thankfully this prompt is not hardlocked)

This is bizarre, I've created the iso, sha1sums are correct, CD label is
'ARCH_201803', but the iso won't boot. I've researched, but these solutions
don't solve the problem:

https://bbs.archlinux.org/viewtopic.php?id=195671
https://superuser.com/questions/519784/error-installing-arch-linux
https://bugs.launchpad.net/bugs/1318400

Check /dev/disk from the recovery prompt, there is no "by-label" directory
under /dev/disk to begin with. Attempting to create 'by-label' and softlinking
/dev/sr0 to /dev/disk/by-label/ARCH_201803 does create a series of additional
errors I/O errors concluding with,

mount: /run/archiso/bootmnt: wrong fs type, bad option, bad superblock on
/dev/sr0, missing codepage or helper system ....

So I'm snakebit and need help. I've never had the system lock during kernel
update before and it has left part of the system thinking it has 4.15.7 and
the rest thinking it is 4.15.8 (but the 4.15.8 update never finished)

(1) How do I go about recovering? 4.15.7 was A-OK. I'm not sure what part of
the install is still 4.15.7 and what's 4.15.8. 59 packages were updated,
including the kernel and lts-kernel, but the initramfs was never regenerated
due to the failure at the 'Install DKMS modules' phase. If I can get the
ARCH_201803 install media to boot properly -- what next?

(2) How do I get around the ERROR: '/dev/disk/by-label/ARCH_201803' device did
not show up after 30 seconds problem? The disk label is correct, it's just not
being seen and mounted by the installer to /run/archiso/bootmnt

Any help greatly appreciated.
--
David C. Rankin, J.D.,P.E.
Guus Snijders via arch-general
2018-03-11 21:08:33 UTC
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Op zo 11 mrt. 2018 21:29 schreef David C. Rankin <
Post by David C. Rankin
All,
I experienced a hard lockup during kernel update to 4.15.8 on a Supermicro
Dual Opteron Quad-core box.
[cd problem]

Just to make sure; can you run a memtest on this machine? It's a bit of a
long shot, but hard lockups are suspicious. Especially since the CD also
acts strangely.
Though an overheating CPU could also cause these symptons.


Mvg, Guus Snijders
David C. Rankin
2018-03-11 22:32:33 UTC
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Post by Guus Snijders via arch-general
Op zo 11 mrt. 2018 21:29 schreef David C. Rankin <
Post by David C. Rankin
All,
I experienced a hard lockup during kernel update to 4.15.8 on a Supermicro
Dual Opteron Quad-core box.
[cd problem]
Just to make sure; can you run a memtest on this machine? It's a bit of a
long shot, but hard lockups are suspicious. Especially since the CD also
acts strangely.
Though an overheating CPU could also cause these symptons.
Mvg, Guus Snijders
This was a nightmare. It's not a CD problem, it's a problem with the system
seeing the CD Label and/or creating the /dev/disk/by-label directory in time
for the link to be created.

I burned 3 different CD's from the .iso (validating the sha1sum). I burned 2
of them from the Arch server next to this box running the 4.15.8 kernel whose
update went fine. I burned per:

https://wiki.archlinux.org/index.php/Optical_disc_drive#Burning_an_ISO_image_to_CD.2C_DVD.2C_or_BD

cdrecord -v -sao dev=/dev/sr0 archlinux-2018.03.01-x86_64.iso

and I burned from K3b as well. No change. Same failure.

So even though this box cannot boot from a USB, I created a USB install media
and plugged it into a USB port so that maybe its ARCH_201803 drive label would
be seen. (I think the problem is the .iso CD lsblk Label isn't updated during
boot for some reason)

Low-and-behold... It worked!. I was able to boot to the Arch install prompt.
mdadm ran and assembled my arrays. I arch-chrooted to /mnt and then
reinstalled the kernel, kernel-lts and then had to reinstall the other 57
packages.

I don't know what the hiccup was, but for this box it was a death sentence. No
linker modules updated, only 2 out of 16 post install processes run. That
really leaves you in a bad way...

Fixed now.

So to recap, the key to solving the 30 second CD label not seen bug, was to
put a USB install media in a USB port before boot so the drive would be
activated and the LABEL available when it got to the find disk/by-label part
of the installer boot. (I hope I recall this trick 2 years from now when
something like this happens again...)
--
David C. Rankin, J.D.,P.E.
Carsten Mattner via arch-general
2018-03-12 01:03:06 UTC
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Post by David C. Rankin
This was a nightmare. It's not a CD problem, it's a problem with the system
seeing the CD Label and/or creating the /dev/disk/by-label directory in
time for the link to be created.
Hi David,

so in the end you were able to boot off usb, right?

Also, the nightmare you had to work through can be avoided on servers
where you run illumos or FreeBSD by way of ZFS boot environments (BE).
Basically, it's like Windows style snapshots of core files you can
boot, in case stuff goes south.

I didn't post this to the list, since it mentions ZFS, and that alone
might get some people pissed off.
Carsten Mattner via arch-general
2018-03-12 01:04:14 UTC
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Or I actually did post it to the list by accident.

Please don't flame me for mention ZFS boot environments as a technique
available for FOSS servers.
Post by Carsten Mattner via arch-general
Post by David C. Rankin
This was a nightmare. It's not a CD problem, it's a problem with the system
seeing the CD Label and/or creating the /dev/disk/by-label directory in
time for the link to be created.
Hi David,
so in the end you were able to boot off usb, right?
Also, the nightmare you had to work through can be avoided on servers
where you run illumos or FreeBSD by way of ZFS boot environments (BE).
Basically, it's like Windows style snapshots of core files you can
boot, in case stuff goes south.
I didn't post this to the list, since it mentions ZFS, and that alone
might get some people pissed off.
Celti Burroughs via arch-general
2018-03-12 01:51:23 UTC
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On Mon, 12 Mar 2018 01:04:14 +0000
Post by Carsten Mattner via arch-general
Or I actually did post it to the list by accident.
Please don't flame me for mention ZFS boot environments as a technique
available for FOSS servers.
Post by Carsten Mattner via arch-general
Post by David C. Rankin
This was a nightmare. It's not a CD problem, it's a problem with the system
seeing the CD Label and/or creating the /dev/disk/by-label
directory in time for the link to be created.
Hi David,
so in the end you were able to boot off usb, right?
Also, the nightmare you had to work through can be avoided on
servers where you run illumos or FreeBSD by way of ZFS boot
environments (BE). Basically, it's like Windows style snapshots of
core files you can boot, in case stuff goes south.
I didn't post this to the list, since it mentions ZFS, and that
alone might get some people pissed off.
I don't see why anyone should get pissed off. I mean, ArchZFS[1] is
definitely a thing that works reasonably well, and the wiki page[2]
specifically mentions boot environments and beadm.

~Celti

[1]: https://github.com/archzfs/archzfs
[2]: https://wiki.archlinux.org/index.php/Installing_Arch_Linux_on_ZFS
Carsten Mattner via arch-general
2018-03-12 02:00:42 UTC
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Post by Celti Burroughs via arch-general
On Mon, 12 Mar 2018 01:04:14 +0000
Post by Carsten Mattner via arch-general
Or I actually did post it to the list by accident.
Please don't flame me for mention ZFS boot environments as a technique
available for FOSS servers.
Post by Carsten Mattner via arch-general
Post by David C. Rankin
This was a nightmare. It's not a CD problem, it's a problem with the system
seeing the CD Label and/or creating the /dev/disk/by-label
directory in time for the link to be created.
Hi David,
so in the end you were able to boot off usb, right?
Also, the nightmare you had to work through can be avoided on
servers where you run illumos or FreeBSD by way of ZFS boot
environments (BE). Basically, it's like Windows style snapshots of
core files you can boot, in case stuff goes south.
I didn't post this to the list, since it mentions ZFS, and that
alone might get some people pissed off.
I don't see why anyone should get pissed off. I mean, ArchZFS[1] is
definitely a thing that works reasonably well, and the wiki page[2]
specifically mentions boot environments and beadm.
I'm happy to hear that. My rationale is based on past observations
of needlessly heated arguments and ZFS, due to its license splitting
the Linux community in half, appearing to be perfect fuel for such
a thread.

Thanks for the wiki links. Never used ZFS on Linux because I avoid
out of kernel patches. Maybe I will give it a try on Linux as well.
Eli Schwartz via arch-general
2018-03-12 21:29:12 UTC
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Post by Carsten Mattner via arch-general
I'm happy to hear that. My rationale is based on past observations
of needlessly heated arguments and ZFS, due to its license splitting
the Linux community in half, appearing to be perfect fuel for such
a thread.
Thanks for the wiki links. Never used ZFS on Linux because I avoid
out of kernel patches. Maybe I will give it a try on Linux as well.
Well yes, the main reason people get heated about it I think is because
it is out-of-tree kernel modules and as such are less reliably stable or
some such.

Based on how well archzfs keeps their binary repos up to date, I'm not
100% convinced on the stability. Moreso consider that it's difficult to
bootstrap a system without zfs available, and if their binary repo does
not match the current archiso...
--
Eli Schwartz
Bug Wrangler and Trusted User
Carsten Mattner via arch-general
2018-03-12 22:24:37 UTC
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Post by Eli Schwartz via arch-general
Post by Carsten Mattner via arch-general
I'm happy to hear that. My rationale is based on past observations
of needlessly heated arguments and ZFS, due to its license splitting
the Linux community in half, appearing to be perfect fuel for such
a thread.
Thanks for the wiki links. Never used ZFS on Linux because I avoid
out of kernel patches. Maybe I will give it a try on Linux as well.
Well yes, the main reason people get heated about it I think is because
it is out-of-tree kernel modules and as such are less reliably stable or
some such.
Based on how well archzfs keeps their binary repos up to date, I'm not
100% convinced on the stability. Moreso consider that it's difficult to
bootstrap a system without zfs available, and if their binary repo does
not match the current archiso...
I'll stay away from it, thanks. I saw that Alpine Linux has good ZFS
support, but I didn't do anything serious with it. When it comes to
filesystems, I'm conservative, EXT4 and XFS on Linux. It's a pity
there's no modern filesystem to share volumes between FOSS kernels.
It's all some compromise that you might or might not accept.

My current recommendation if one is looking for ZFS:

(1) FreeBSD good enough, no linux binaries needed? Go with that.
(2) illumos derivative work for you in terms of drivers _and_
you need Linux binaries to run seamlessly? illumos lx branded
zones are your solution then. You can even dtrace a linux zone
from the illumos outer environment. It's like FreeBSD Jails
on steroids without the immaturity and chaos of Linux containers.
Crossbow is nice, too.

Keep in mind both 1 and 2 start off with a desire to use 1st class
native ZFS support. illumos #1 problem is the unneeded distro
fragmentation when the community is so small anyway. But they're
collaborating on the base and core system very well. The main issue
is porting or writing drivers. To this day I wonder why Google for
all of its Java language reliance didn't buy Sun liberate it fully.
Past fights over the language and Apache Java might have led Sun
to block any Google talks.
Leonid Isaev via arch-general
2018-03-12 22:57:48 UTC
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Post by Carsten Mattner via arch-general
Post by Eli Schwartz via arch-general
Post by Carsten Mattner via arch-general
I'm happy to hear that. My rationale is based on past observations
of needlessly heated arguments and ZFS, due to its license splitting
the Linux community in half, appearing to be perfect fuel for such
a thread.
Thanks for the wiki links. Never used ZFS on Linux because I avoid
out of kernel patches. Maybe I will give it a try on Linux as well.
Well yes, the main reason people get heated about it I think is because
it is out-of-tree kernel modules and as such are less reliably stable or
some such.
Based on how well archzfs keeps their binary repos up to date, I'm not
100% convinced on the stability. Moreso consider that it's difficult to
bootstrap a system without zfs available, and if their binary repo does
not match the current archiso...
I'll stay away from it, thanks. I saw that Alpine Linux has good ZFS
support, but I didn't do anything serious with it. When it comes to
filesystems, I'm conservative, EXT4 and XFS on Linux. It's a pity
there's no modern filesystem to share volumes between FOSS kernels.
It's all some compromise that you might or might not accept.
What's wrong with btrfs? Yeah, I know it is not marked "stable", but this is
just a label. And people shying away from it doesn't help in advancing its
stability either.

Cheers,
--
Leonid Isaev
Eli Schwartz via arch-general
2018-03-12 23:04:49 UTC
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Post by Leonid Isaev via arch-general
Post by Carsten Mattner via arch-general
I'll stay away from it, thanks. I saw that Alpine Linux has good ZFS
support, but I didn't do anything serious with it. When it comes to
filesystems, I'm conservative, EXT4 and XFS on Linux. It's a pity
there's no modern filesystem to share volumes between FOSS kernels.
It's all some compromise that you might or might not accept.
What's wrong with btrfs? Yeah, I know it is not marked "stable", but this is
just a label. And people shying away from it doesn't help in advancing its
stability either.
Well, I think the only outstanding issue really with btrfs is raid5/6
support. Maybe this scares people away?
--
Eli Schwartz
Bug Wrangler and Trusted User
Carsten Mattner via arch-general
2018-03-12 23:17:21 UTC
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Post by Leonid Isaev via arch-general
Post by Carsten Mattner via arch-general
Post by Eli Schwartz via arch-general
Post by Carsten Mattner via arch-general
I'm happy to hear that. My rationale is based on past observations
of needlessly heated arguments and ZFS, due to its license splitting
the Linux community in half, appearing to be perfect fuel for such
a thread.
Thanks for the wiki links. Never used ZFS on Linux because I avoid
out of kernel patches. Maybe I will give it a try on Linux as well.
Well yes, the main reason people get heated about it I think is because
it is out-of-tree kernel modules and as such are less reliably stable or
some such.
Based on how well archzfs keeps their binary repos up to date, I'm not
100% convinced on the stability. Moreso consider that it's difficult to
bootstrap a system without zfs available, and if their binary repo does
not match the current archiso...
I'll stay away from it, thanks. I saw that Alpine Linux has good ZFS
support, but I didn't do anything serious with it. When it comes to
filesystems, I'm conservative, EXT4 and XFS on Linux. It's a pity
there's no modern filesystem to share volumes between FOSS kernels.
It's all some compromise that you might or might not accept.
What's wrong with btrfs? Yeah, I know it is not marked "stable", but this
is just a label. And people shying away from it doesn't help in advancing
its stability either.
btrfs never got on my radar because it's Linux only and its instability
is a blocker. If I have to be careful how I use a filesystem even when
I didn't explicitly enable beta features, I'm too scared to put my files
on it. If I were a Suse Enterprise customer, I might use it, but Red Hat
isn't behind it anymore, so it's like Reiser3 back in the day. Only Suse
was putting their weight behind it. Well Facebook has developers on it,
but Facebook isn't a distro developer and can't be trusted with continued
maintenance, since they might switch on a weekend to some Facebook-FS.
Facebook has too many engineers and is reinventing stuff in-house a lot.

btrfs and zfs suffer from design limitations, but zfs has been stable
and in petabyte production for a long time across many organizations.
btrfs is one of many future Linux filesystems with no clear winner
so far. It looks like XFS will gain full checksums and scrubbing
before btrfs gets reliable and Red Hat's XFS++ work will provide
snapshots. It's like git replacing bitkeeper in 2005. Seems like
XFS++ will do the same with btrfs left to history of experiments.

All I want is a modern filesystem whose volume I can share without
exposing it via a network protocol.
Carsten Mattner via arch-general
2018-03-12 23:26:58 UTC
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It almost looks like filesystem development doesn't fit Linux kernel
development style
of iterating constantly and evolving with time. btrfs has had the same
time as zfs
had in-house at Oracle before it was declared publicly stable, and
there are still
buggy/unfinished corners.

If you look at past successful Linux filesystems it's either an existing design
that was generally amenable to certain extensions and has evolved in-tree or
came designed and implemented from a different platform (JFS, XFS, quite a few
more). EXT4 is the reliable workhorse if inodes aren't a problem and you don't
mind time to allocate and upper bounds thereof. It evolved step by step from
EXT2 to EXT3 to EXT4, all the while having stable core features and experimental
features. btrfs is busy implementing features promised 10 years ago and there
are bugs in regular use if you're not careful.

Developing a filesystem is hard and there's no room for mistakes. Most
productive
filesystem development is happening in XFS and EXT4 teams with the former being
in a nice stable maintenance mode. If you haven't tried XFS in the last 3 years,
give it a test run. The old issues of being optimized for certain workloads have
been fixed years ago. It's a good replacement for EXT4 if you need its features
and tools.
Carsten Mattner via arch-general
2018-03-12 23:30:28 UTC
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Sorry for letting gmail butcher wrapping/breaks. Someone at Google
needs to be demoted for that anti-feature. I should remember to never
edit in gmail's text box but use my normal editor as usual.
Leonid Isaev via arch-general
2018-03-13 00:10:39 UTC
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Post by Carsten Mattner via arch-general
Post by Leonid Isaev via arch-general
What's wrong with btrfs? Yeah, I know it is not marked "stable", but this
is just a label. And people shying away from it doesn't help in advancing
its stability either.
btrfs never got on my radar because it's Linux only and its instability
is a blocker. If I have to be careful how I use a filesystem even when
I didn't explicitly enable beta features, I'm too scared to put my files
on it. If I were a Suse Enterprise customer, I might use it, but Red Hat
isn't behind it anymore, so it's like Reiser3 back in the day. Only Suse
was putting their weight behind it. Well Facebook has developers on it,
but Facebook isn't a distro developer and can't be trusted with continued
maintenance, since they might switch on a weekend to some Facebook-FS.
Facebook has too many engineers and is reinventing stuff in-house a lot.
This is all corporate politics, but see first comment here [1]. And you still
haven't explained what instability? I use btrfs on all my machines, including
its subvolume/snapshot features to protect against failed updates (essentially,
I reimplemented some features of snapper in bash :) because I don't like dbus).

Of course, you need to do scrubbing regularly, but it's trivial to write a cron
job/systemd timer for this task...
Post by Carsten Mattner via arch-general
btrfs and zfs suffer from design limitations, but zfs has been stable
and in petabyte production for a long time across many organizations.
btrfs is one of many future Linux filesystems with no clear winner
so far.
If noone uses it, then sure, btrfs will remain an underdog of filesystems.
Also, if you care about petabyte production, you should know better than asking
on this list...
Post by Carsten Mattner via arch-general
All I want is a modern filesystem whose volume I can share without
exposing it via a network protocol.
Hmm, btrfs-send(1)?

[1] https://news.ycombinator.com/item?id=14907771

Cheers,
--
Leonid Isaev
John Ramsden via arch-general
2018-03-13 03:07:39 UTC
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Post by Leonid Isaev via arch-general
What's wrong with btrfs? Yeah, I know it is not marked "stable", but this
is just a label. And people shying away from it doesn't help in advancing
its stability either.
It might be good for experimentation and possibly a desktop, but if you're actually storing a lot of files, you probably want a filesystem marked as stable. The fact that it is not marked stable implies the developers still think there is some sort of insufficiency.

ZFS is known to be a world-class filesystem and could probably be considered one of the most system agnostic file systems now considering it is available on FreeBSD, Solaris, most Linux distributions, and even Windows and macOS. While the macOS and Windows ports are probably not at a point where they are suitable for widespread use - since they are still fairly new - you could at least mount a pool on those systems and read your data, the same can't be said for btrfs.

For anyone not happy with dkms, the archzfs repo [1] offers great support for ZFS in binary form, and I've been using it for a few years now with no problems.

[1] https://github.com/archzfs/archzfs
--
John Ramsden
Eli Schwartz via arch-general
2018-03-13 03:33:35 UTC
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Post by John Ramsden via arch-general
For anyone not happy with dkms, the archzfs repo [1] offers great
support for ZFS in binary form, and I've been using it for a few
years now with no problems.
The most important part of using zfs is installing it. Especially
considering the reason zfs was mentioned in this thread was as a
proposal that someone might want to consider installing it, the ability
to actually do so would be nice.

You cannot install an Arch Linux system on zfs, without the zfs kernel
drivers compiled for your running kernel.

You cannot build those kernel modules on the Arch installation media,
without doing a full system upgrade and installing the compiler
toolchain, while holding back the kernel itself and hunting for the
kernel headers matching the kernel from the ISO, then getting the zfs
sources and building that too.
On a ramdisk overlay filesystem.

Now, in theory the archzfs repo provides some archiso packages for
exactly this use case. Except no they don't, because their archiso
packages have not been updated since October...

This is less than entirely impressive. They have rebuilt everything
else, why not this?
--
Eli Schwartz
Bug Wrangler and Trusted User
John Ramsden via arch-general
2018-03-13 04:30:05 UTC
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Actually, you can easily create an arch ISO with ZFS embedded into it. It's what I do, and it takes about five minutes to create.

https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
--
John Ramsden
Post by Eli Schwartz via arch-general
Post by John Ramsden via arch-general
For anyone not happy with dkms, the archzfs repo [1] offers great
support for ZFS in binary form, and I've been using it for a few
years now with no problems.
The most important part of using zfs is installing it. Especially
considering the reason zfs was mentioned in this thread was as a
proposal that someone might want to consider installing it, the ability
to actually do so would be nice.
You cannot install an Arch Linux system on zfs, without the zfs kernel
drivers compiled for your running kernel.
You cannot build those kernel modules on the Arch installation media,
without doing a full system upgrade and installing the compiler
toolchain, while holding back the kernel itself and hunting for the
kernel headers matching the kernel from the ISO, then getting the zfs
sources and building that too.
On a ramdisk overlay filesystem.
Now, in theory the archzfs repo provides some archiso packages for
exactly this use case. Except no they don't, because their archiso
packages have not been updated since October...
This is less than entirely impressive. They have rebuilt everything
else, why not this?
--
Eli Schwartz
Bug Wrangler and Trusted User
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Eli Schwartz via arch-general
2018-03-13 13:41:46 UTC
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Post by John Ramsden via arch-general
Actually, you can easily create an arch ISO with ZFS embedded into
it. It's what I do, and it takes about five minutes to create.
https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
Yes, and it also requires an Arch system (or at least one with pacman
available) to run mkarchiso, pacstrap, copy the initcpio configs from
mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
don't really consider this a viable generic solution...
--
Eli Schwartz
Bug Wrangler and Trusted User
Leonid Isaev via arch-general
2018-03-13 13:47:44 UTC
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Post by Eli Schwartz via arch-general
Post by John Ramsden via arch-general
Actually, you can easily create an arch ISO with ZFS embedded into
it. It's what I do, and it takes about five minutes to create.
https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
Yes, and it also requires an Arch system (or at least one with pacman
available) to run mkarchiso, pacstrap, copy the initcpio configs from
mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
don't really consider this a viable generic solution...
Can't this be done from any distro using Arch rootfs?

Cheers,
--
Leonid Isaev
Eli Schwartz via arch-general
2018-03-13 14:39:58 UTC
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Post by Leonid Isaev via arch-general
Post by Eli Schwartz via arch-general
Post by John Ramsden via arch-general
Actually, you can easily create an arch ISO with ZFS embedded into
it. It's what I do, and it takes about five minutes to create.
https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
Yes, and it also requires an Arch system (or at least one with pacman
available) to run mkarchiso, pacstrap, copy the initcpio configs from
mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
don't really consider this a viable generic solution...
Can't this be done from any distro using Arch rootfs?
Like I said, this can be done from any system which has pacman and
mkinitcpio available. That means:

1) Arch Linux
2) Gentoo, which has a pacman package and IIRC also provides mkinitcpio
as an option alongside dracut.
3) Any Linux distribution if you have chrooted into the bootstrap image
4) Windows (or any operating system, really), by using a virtual machine

Certainly, anything is *possible* if you put in enough work. But making
something annoyingly difficult to do is, as I said, hardly a generic
solution.
--
Eli Schwartz
Bug Wrangler and Trusted User
Carsten Mattner via arch-general
2018-03-13 20:51:01 UTC
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Post by Eli Schwartz via arch-general
Like I said, this can be done from any system which has pacman and
1) Arch Linux
2) Gentoo, which has a pacman package and IIRC also provides mkinitcpio
as an option alongside dracut.
3) Any Linux distribution if you have chrooted into the bootstrap image
4) Windows (or any operating system, really), by using a virtual machine
Certainly, anything is *possible* if you put in enough work. But making
something annoyingly difficult to do is, as I said, hardly a generic
solution.
True and Alpine Linux supports (3.5) ZFS on install which I didn't confirm
because, like I said, I don't use ZFS on Linux. I mean that if Arch
ZFS developers want to, they can leverage work from other distros.
I guess it's a good thing Arch has no installer or otherwise there
might be a heated debate whether ZFS should be an option :).
David C. Rankin
2018-03-12 21:07:12 UTC
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Post by Carsten Mattner via arch-general
Hi David,
so in the end you were able to boot off usb, right?
Also, the nightmare you had to work through can be avoided on servers
where you run illumos or FreeBSD by way of ZFS boot environments (BE).
Basically, it's like Windows style snapshots of core files you can
boot, in case stuff goes south.
I didn't post this to the list, since it mentions ZFS, and that alone
might get some people pissed off.
Partially,

I had to boot from the CD, because the BIOS (AMI circa 2005) does not have
the capability to boot from USB. But, by using both the CD and USB (having
plugged the USB in before boot), when the boot from CD got to the point it
looked for the disk label ARCH_201803, it found the USB stick and was able to
mount it at /run/archiso/bootmnt where the boot from CD alone always fails.

No worries about the filesystem. I don't care whether it is xfs, zfs, ext,
but it won't be btrfs, I just dance with the one that brung me. I did do a
filesystem comparison several months ago, and since I never reach limitations
of ext inodes anyway, zfs didn't have anything else that really moved me to
switch. I don't max my disks anyway. If I'm running 1T drives and hit 850G,
I'll go 3T and so on...
--
David C. Rankin, J.D.,P.E.
Kyle Bassett via arch-general
2018-03-13 08:40:29 UTC
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Hi Carsten, I'm glad you ended up posting this to the list. Very useful
info, even if I never end up using it.

The rest of this thread has some great content too.

Thanks all!



On Mar 11, 2018 21:03, "Carsten Mattner via arch-general" <
Post by David C. Rankin
Post by David C. Rankin
This was a nightmare. It's not a CD problem, it's a problem with the
system
Post by David C. Rankin
seeing the CD Label and/or creating the /dev/disk/by-label directory in
time for the link to be created.
Hi David,
so in the end you were able to boot off usb, right?
Also, the nightmare you had to work through can be avoided on servers
where you run illumos or FreeBSD by way of ZFS boot environments (BE).
Basically, it's like Windows style snapshots of core files you can
boot, in case stuff goes south.
I didn't post this to the list, since it mentions ZFS, and that alone
might get some people pissed off.
David C. Rankin
2018-03-17 06:19:00 UTC
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Post by David C. Rankin
I don't know what the hiccup was, but for this box it was a death sentence. No
linker modules updated, only 2 out of 16 post install processes run. That
really leaves you in a bad way...
Well, it seems it was an issue and not just a hiccup. I posted the issue to
the linux-raid list on kernel.org (title: "4.15.8 Kernel - Strange linux-raid
behavior, not sure where to send it.") and it seems there have been other hit
with it as well:

https://bugzilla.kernel.org/show_bug.cgi?id=198861
https://bugzilla.redhat.com/show_bug.cgi?id=1552124

Thankfully, since I installed the 4.15.9 kernel, it seems to be fixed (I still
have more testing to do, but it looks good)

So if anyone else is hit with a raid 1 issue on multi-cpu boxes, there is more
information at the links above.

(p.s. - not that my opinion matters on the bug tracker choice, but for the
number of bugs Arch has (compared to Mozilla, etc.) I don't think there would
be much of a delay issue regardless which packages is used - ease of
maintenance and an easy migration path probably wins the day)
--
David C. Rankin, J.D.,P.E.
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