Re: swap space in file on inconsystent file system

[David Brownlee <abs%absd.org@localhost>]

On 7 June 2018 at 14:03, Steve Blinkhorn <steve%prd.co.uk@localhost> wrote:
> I have a remote server (about to be replaced, but still in service and
> needs to stay that way until a replacement is fully commissioned) that
> has just developed a single bad sector.  The result has been that
> automatic backups using rsync have failed, and manual intervention is
> needed.
>
> There are also numerous sleeping processes that refuse to be killed,
> almost all in the 'tstile' state (this is i386 7.0).
>
> #top
>
> 140 processes: 133 sleeping, 5 zombie, 2 on CPU
> CPU states:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt, 100% idle
> Memory: 107M Act, 63M Inact, 6968K Wired, 13M Exec, 11M File, 160M Free
> Swap: 1128M Total, 345M Used, 783M Free
>
> Most of the swap space is in a file on the file system concerned.
>
> fsck -n on the other file systems shows a small handful of unreferenced
> files in /var (a separate file system), but no other issues.
>
> I need to get this machine into a sane condition without being able to
> access it in single user mode (because there is no remote console
> access).
>
> How should I proceed?

First action might be to add a --exclude to the rsync (or move the
affected file to a different location on the filesystem excluded from
rsync).

You could work out the affected block and dd zeros to it via the raw
device, but if the system is going away I'd probably not worry about
that.

Other questions which might affect approach include:
- How long before the new system is deployed
- Do you know if the system would reboot cleanly
- Is the root filesystem clean

David