[pacman-dev] Disk Space

[Dan McGee]

On Mon, Feb 23, 2009 at 11:56 AM, Aaron Griffin <aaronmgriffin at gmail.com> wrote:
> On Mon, Feb 23, 2009 at 1:47 AM, Brendan Hide <brendan at swiftspirit.co.za> wrote:
>> Again, this will be properly fixed as soon as pacman correctly takes into
>> account the errors given when doing the actual deployment. Personally, I
>> like the idea of adding sanity checks - but only if they're done properly.
>> ;)
>
> I wouldn't say that - we've talked about "proper transactions" for a
> long time, and are still nowhere near a proper solution. So don't
> expect this to be fixed soon, unless you're writing the patches :)
>
> The problem with errors given during actual file operations is... what
> do we do when extracting a file fails? How do we return to normalcy?
> We can't. The best we can do is bail out, perhaps before updating the
> DB.
>
> For instance, if I have foobar-1.0 installed, and upgrading to 1.1
> fails due to disk space in the middle of the upgrade, what do we do?
> Do we leave foobar half upgraded and keep the DB entry at 1.0? This
> would allow us to reinstall foobar at the next upgrade when disk space
> is fixed, but leaves foobar in a possibly non-functioning state then.
> What happens if this is a critical package like, say, glibc. You can't
> clean up your disk space manually if glibc is borked and you can't
> even use "rm"

This is not an easy problem by any means as Aaron stated. A few other things:

* Say we warn a user if they have less than 100 MB left. You already
pointed out that doesn't work for some large packages. What if I have
180 GB left, but my /boot partition is super-low on space? It isn't
like Windows where I pretty much need to check C:\ and that is it.
* The current order of operations is download, remove 1 package,
install 1 package, remove 1, install 1, ... Without making this a more
atomic sequence, we can really run into problems.

Whatever we do, we can't add in what we had before- that method was
horrible. I do have two patches in my working branch dealing with
space issues, but I'm not super happy with them:
http://code.toofishes.net/cgit/dan/pacman.git/log/?h=working (see the
top two patches).

-Dan