[squid-users] External ACL Queue Overload

Hello,

I'm seeing a lot of these messages in one of my proxies:

aclMatchExternal: 'nt_group' queue overload. Using stale result.

What does that mean? Previously I had problems with queue overloads
but it used to deny access. Also this particular proxy seem to be a
lot slower than the other ones (we currently operate several proxies
balanced by a DNS round robin).

Is there anything I can do to improve its performance and get rid of
these warnings?

The acl and auth helper is the following:

auth_param ntlm program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
auth_param ntlm children 256
auth_param ntlm keep_alive on

external_acl_type nt_group ttl=10 concurrency=5 children=20 %LOGIN
/usr/lib64/squid/wbinfo_group.pl

-- 
Diego Lima