illumos gate

mountd(1m) is affected by this (cite from rpc_control(3nsl) man page):

     By default, RPC servers are limited to  a  maximum  of  1024
     file  descriptors  or  connections due to limitations in the
     historical       interfaces       svc_fdset(3NSL)        and
     svc_getreqset(3NSL).  Applications  written  to use the pre-
     ferred     interfaces      of      svc_pollfd(3NSL)      and
     svc_getreq_poll(3NSL)  can  use  an unlimited number of file
     descriptors.  Setting info to point to  a  non-zero  integer
     and  op to RPC_SVC_USE_POLLFD removes the limitation.

We saw under high load that mountd(1m) started to reject new incoming connections because of this limit. The limit is enforced here in do_accept():

790    if (RPC_FD_NOTIN_FDSET(destfd)) {
791        (void) syslog(LOG_ERR, errstring, do_accept_str,
792                        svc_vc_fderr);
793        (void) t_close(destfd);
794        (void) t_snddis(srcfd, tcp);
795        errno = EBADF;
796        t_errno = TBADF;
797        return;
798    }