[Users] Ploop filesystem provisioned incorrectly (wrong size)

[Kir Kolyshkin]

On 07/26/2014 08:50 PM, Kir Kolyshkin wrote:
> On 07/26/2014 12:45 PM, Kevin Holly wrote:
> > On 23/07/14 09:34, Kir Kolyshkin wrote:
> >
> > I just talked with a L3 Supporter of SolusVM and they told me that
> > this seems to be a well known vzctl bug.
>
> Great, can they point out to a bug in bugzilla.openvz.org?
>
> >
> > What SolusVM basically does is this on creation of the container:
> >
> > https://ezcrypt.it/ag9n#QcRKRX8DIFdFKJv6ZNFahTSt
>
> Thanks for providing this!
>
> Lots of weird/stupid things overall... But let's stay on topic.
>
> Here is the first relevant line:
>
> > vzctl create 134 --layout ploop --diskspace 262144000K:262144000K [...]
>
> Here they set diskspace to 250G on creation.
>
> And this is the second relevant line:
>
> > vzctl set 134 --diskspace 262144000K:262144000K --diskinodes 131072000:131072000 --save
>
> Here they resize it with 250G diskspace and 131072000 of diskinodes.

I just discovered that my analysis are not entirely correct (although
the result
is correct, it's just the details), so here's a small update.

vzctl set --diskinodes is ignored for ploop, as there is no way to
change the number
of inodes for already-created file system (so --diskinodes can only be
specified on
creation).

Now, it seems that the sample configuration file used on creation:

> vzctl create 134 --layout ploop --diskspace 262144000K:262144000K \
>   --ostemplate debian-7-amd64-minimal --config vswap-solus

i.e. vswap-solus sample config file
(/etc/vz/conf/ve-vswap-solus.conf-sample)
actually contains DISKINODES=131072000 line which is used by vzctl create.
I can't tell it for sure since you don't provide the file itself but I
don't see any other explanation


>
> Now, ext4 reserve one inode per 16KB of diskspace on filesystem creation
> (you can think of it as a heuristic that an average file is 16KB of
> size), and
> there is no way to change a number of inodes on an existing filesystem.
> Well, there is one -- you need to resize the filesystem itself.
>
> As vzctl is told that 131072000 of diskinodes are required, it resizes the
> file system to the size sufficient to hold the requested number of inodes,
> which is 131072000*16K, or 2TB. Then, as diskspace is set to 250G, vzctl
> steals the rest of the space by using an invisible hidden (empty)
> balloon file.
> So, while the internals are tricky, the result is exactly as
> requested, i.e.
> a filesystem with (about) 250 GB of diskspace, but with 131072000 inodes.
>
> Now, if I can, I'd say that the number of inodes requested is way too high
> for the given disk space, unless it's really going to be used to hold that
> high number of small (about 2K on average) files.
>
> >
> > And this is the reinstallation process of the container:
> >
> > https://ezcrypt.it/cg9n#sHQJeiV7Y6bl6zyBBjS60oLN
> >
> > Where the config looks exactly like this:
> >
> > https://ezcrypt.it/dg9n#g2Ico8AknpAtJbAcxkbBQDub
>
> This adds nothing new to the picture and is in line with that
> was seen before.
>
> Now, back to "vzctl bug" that they say exist in versions newer than 4.6.1.
> This diskinodes handing for ploop was added in vzctl 4.7, before that
> diskinodes value was ignored for ploop.
>
> Hope that helps. <shameless plug> By the way, we accept donations now,
> so if you feel like
> helping us back, too, feel free:
> http://openvz.livejournal.com/48757.html </shameless plug>
>
> Kir.
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openvz.org/pipermail/users/attachments/20140729/e59c1b37/attachment.html>