resolver errors

Sven Willenberger sven@dmv.com
Thu Mar 15 19:49:50 UTC 2007


On Thu, 2007-03-15 at 11:35 -0700, Vernon Schryver wrote:
> > From: Sven Willenberger 
> 
> > Having just upgraded dcc-public, dcc-cl-a and dcc-cl-b (.dmv.com) to
> > [12].3.54 I am now seeing the following error in my logfiles :
> >
> > fork(flod_names_resolve_start): Not enough space
> >
> > and as such flooding between my internal peers is failing
> 
> 
> That message means that fork() returned -1 with errno set a value that
> strerror(errno) translated to "Not enough space".
> I suspect that this from `man fork` on a Solaris system is relevant:
> 
> ]   ENOMEM
> ]          There is not enough swap space.
> 
> There is also this in `man mmap`:
> 
> ]    time of the fork(), swap space is reserved in the child  for
> ]    all  private  pages  that  currently  exist  in  the parent;
> ]    thereafter the child's mapping behaves as described above.
> 
> 
> Dccd forks a child to resolve the host names in the /var/dcc/flod file
> so that the parent can keep working while the child waits for DNS
> resolution.  The first thing the child does is close the database, but
> until then the child on some UNIX-like systems might want enough swap
> space to hold the database, particularly when `dccd -F` is used.  If
> there is enough swap space, the cost should be allocating and then
> releasing the swap space without doing any disk I/O.
> 
> Is there a shortage of swap space?  Does adding -f (small f) to DCCD_ARGS
> in /var/dcc/dcc_conf make this problem go away?

Ahh, yes, there is probably not enough swap to hold the entire database
as the machines have swap equal to the amount of ram; it looks as though
flooding seems to be working with one odd exception:

dcc-cl-a.dmv.com shows:
        server-ID 1095  client-ID 1095  15:36:20
 1181   216.240.97.12     (no input)    dcc-public.dmv.com

dcc-public.dmv.com shows:
        server-ID 1181  client-ID 1181  15:23:42
 1002  216.158.54.132                   dcc-flod.etherboy.com
 1095     (no output)   216.240.97.36   dcc-cl-a.dmv.com

oddly enough dcc-cl-a and dcc-cl-b have biderectional flooding as do
dcc-public and dcc-cl-b so I don't know where the hiccup is in the one
direction (from dcc-public -> dcc-cl-a).

I went ahead and added the "-f" option and will see if the fork error
persists. I will probably go ahead and do a fresh install of the dccd
from scratch (versus updatedcc) just to see if that helps.

Sven




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