Subject: Re: [vserver] Guest on GlusterFS - /var/run/utmp: File too large
From: Gordan Bobic <gordan@bobich.net>
Date: Wed, 03 Oct 2012 10:13:45 +0100

On 10/03/2012 09:54 AM, Oliver Welter wrote:
> Hi Herbert
>
> On 01.10.2012 17:39, Herbert Poetzl wrote:
>> On Mon, Oct 01, 2012 at 01:43:19PM +0200, Oliver Welter wrote:
>>> Hi,
>>> I am experimenting with vserver and glusterfs - I guess that this is a
>>> glusterfs issue but perhaps somebody here has an idea.
>>> I am creating my root filesystem from a read-only root and an overlay
>>> filesystem using aufs. This is working fine with normal blockdevices. I
>>> now tried to replace the writeable partition using a glusterfs mount
>>> point, which results in
>>> fakerunlevel: open("/var/run/utmp"): File too large
>> sounds like the file is too large :)
>>
>> check the file sizes on all involved filesystems and
>> compare them to the maximum allowed file size
> Well - the utmp file remaining on the disk after abort is 384 bytes and
> I have no problems to create some larger files so I guess there is some
> issue with locking or the like. As said, I assume thats not really
> related to vserver itself...

It sounds like you have bumped into one of the many issues with 
GlusterFS that arise when you try to use it as a rootfs. You may want to 
have a read through the glusterfs-devel mailing list archives for issues 
like this that I came across when I was using it for similar things 
(e.g. Open Shared Root). The particularly common claim among the 
developers at the time was that "they couldn't reproduce it" - in 
reality they just couldn't be bothered to put together a few VMs to test 
the kind of a setup required to run GLFS as rootfs. From what I've seen 
about GLFS, not much has changed since a few years back other than 
version number inflation and a RH badge.

Do bear in mind that GLFS is extremely susceptible to split-braining if 
you are hoping to do anything interesting like sharing rootfs-es. This 
is borne out of it's lack of having any notion of quorum and node fencing.

Gordan