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Re: Gentoo guys starting a fork of udev

I demand that Kevin Toppins may or may not have written...

> On 19 November 2012 04:23, John Paul Adrian Glaubitz
> <glaubitz@physik.fu-berlin.de> wrote:
>> And thirdly, if you have very large file systems (we have a 30TB hardware
>> raid here, for example), filesystem checks can take forever. If you
>> reboot such a server and it needs to do an fs check, it will be
>> unavailable until the check has finished. With systemd, you can just
>> declare the filesystem as an automount [1] and the system still boots
>> while the filesystem checks are performed.

> First.... the data in the volume won't be available until the fsck
> completes, so the server won't be able to give the data any faster than it
> takes to fsck the volume.


> -> when installing the system, it makes sense to have separate mount points
> for massively large file systems, that way the system can be booted, the
> fsck can be backgrounded, and then autofs can check for when fsck releases
> the file descriptor to the device, and then it can mount it.

Unless the automatic fsck run uncovers some problem which it will not (by
default) automatically fix. In that case, you definitely do not want autofs
mounting the freshly-checked but still broken filesystem.

> If you have a crap ton of programs all waiting for a volume to be
> available, you should use *run levels*. You can have more than just 6
> runlevels btw.

Problem there is that booting isn't necessarily just one line through the run
levels, possibly starting everything in a run level in any order. It's a
directed acyclic graph, and sometimes the dependency information can be
rather complicated.

Hence the current situation where if fsck fails, booting is effectively
suspended pending admin action; a behaviour which seems quite reasonable to
me. Certainly, some things could be improved here, such as reporting which
filesystems are unmounted but remain marked dirty (though it's been a while
since I last had a failed fs check at boot which wasn't something silly and I
know what should be mounted where; even so, if it does something like that
now, all the better).

|  _  | Darren Salt, using Debian GNU/Linux (and Android)
| ( ) |
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How apt the poor are to be proud.

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