[Vm-dev] unix SqueakSource socket 'too many open files' problem

[David T. Lewis]

On Fri, Feb 26, 2021 at 12:04:26PM -0800, tim Rowledge wrote:
>  
> 
> 
> > On 2021-02-25, at 8:04 PM, tim Rowledge <tim at rowledge.org> wrote:
> > 
> > After an hour or so there are 350 entries in that directory, virtually all sockets. I imagine somehow something has caused an issue that ... well, no idea. Pretty sure it isn't going to last for a week at this rate!
> 
> This morning there were 976 fds. So I restarted and watched and .. 18. It's sitting there all happy and as if, as we say in the UK, "butter wouldn't melt in its mouth". What, me? Cause problems? How can you be so cruel to a young server?
> 
> Maybe a port scanning/attack of some sort flooded it?
>

Keep an eye on it, you probably still have a socket leak.

Here is what I saw on the squeaksource.com server a few minutes ago:

  squeaksourcecom at dan:~$ ls -l /proc/16147/fd
  total 0
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 0 -> /dev/null
  l-wx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 1 -> pipe:[11697]
  l-wx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 2 -> pipe:[11697]
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 3 -> /srv/squeaksourcecom/SqueakSource/ss/Pharo
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 4 -> /srv/squeaksourcecom/SqueakSource/squeaksource.8.image
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 6 -> /srv/squeaksourcecom/SqueakSource/SqueakV50.sources
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 7 -> socket:[25825763]
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 8 -> socket:[25825764]
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 06:25 9 -> /srv/squeaksourcecom/SqueakSource/squeaksource.8.changes

And then a few minutes later:

  squeaksourcecom at dan:~$ ls -l /proc/16147/fd
  total 0
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 0 -> /dev/null
  l-wx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 1 -> pipe:[11697]
  l-wx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 2 -> pipe:[11697]
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 3 -> /srv/squeaksourcecom/SqueakSource/ss/metacello
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 4 -> /srv/squeaksourcecom/SqueakSource/squeaksource.8.image
  lr-x------ 1 squeaksourcecom www-data 64 Feb 14 03:25 6 -> /srv/squeaksourcecom/SqueakSource/SqueakV50.sources
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 7 -> socket:[25825763]
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 03:25 8 -> socket:[25825764]
  lrwx------ 1 squeaksourcecom www-data 64 Feb 14 06:25 9 -> /srv/squeaksourcecom/SqueakSource/squeaksource.8.changes

If your server is not actively handling requests, you should see similar
socket usage. You'll see more file descriptors when you are using Magma,
but keep an eye on the socket entries, and they should not accumulate
over time.

Dave