Help -- OnLine server refuses connections

I'm running INFORMIX-OnLine Version 7.20.UC3 Once or twice a day (possible correlated with heavy load) the server abruptly stops accepting connections. More details follow. Any tips or suggestions would be greatly appreciated. Please reply by email. Thanks! David Anderson anderson@tunes.com ------------------ When the server is in this state, an ESQL client hangs with the following stack: Program received signal SIGINT, Interrupt. 0x3ff83058a18 in usleep_thread () (gdb) where #0 0x3ff83058a18 in usleep_thread () #1 0x3ff830aadf4 in __sleep () #2 0x1200ea9c8 in ifxOS_sleep () at osmutex.c:705 #3 0x1200d2210 in connshm () at shm_fe.c:719 #4 0x1200cde74 in tlConnect () at tl.c:152 #5 0x1200d9168 in slSQIreq () at asfslsqi.c:857 #6 0x1200cca38 in pfConReq () at asfpfsqi.c:2413 #7 0x1200c83b8 in cmReqSync () at cm.c:2222 #8 0x1200c6d28 in cmConReq () at cm.c:541 #9 0x1200bfab8 in ascRequest () at al.c:419 #10 0x1200bd55c in ASF_Call () at asfapi.c:617 #11 0x1200a9828 in asf_connect () at iqconnct.c:907 #12 0x1200aa584 in _iqconnect () at iqconnct.c:1364 #13 0x1200ac1f4 in _sqs_ () at iqconnct.c:2508 #14 0x12009d890 in _iqdbase () at iqsimple.c:482 ----------- And here's a typical output of onstat when the server is in this state: Userthreads address flags sessid user tty wait tout locks nreads nwrites 20033e028 ---P--D 1 informix - 0 0 0 69 384 20033e658 ---P--F 0 informix - 0 0 0 0 3532 20033ec88 ---P--B 8 informix - 0 0 0 0 0 20033f2b8 ---P--D 66 informix - 0 0 0 0 0 20033ff18 Y--P--- 155 anderson ttyp6 2006f2340 0 1 19653 96 200340b78 Y--P--- 176 anderson ttyp8 2006a31a0 0 1 229609 0 6 active, 128 total, 38 maximum concurrent Profile dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached 163276 436027 3919489 95.83 5562 31648 8938 37.77 isamtot open start read write rewrite delete commit rollbk 3341678 236085 456371 1177677 757 98 1 1042 0 ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes 0 0 0 1441.10 96.92 17 34 bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans 50869 2 2027917 0 0 8 582 226 ixda-RA idx-RA da-RA RA-pgsused lchwaits 85118 1268 3808 86863 8