trouble

Hi folks, We've been having some strange problems this week. We run an ever-growing number of small databases on Informix 7.2n, running on IRIX 6.n. For ages, life has been good, but suddenly we're seeing the following in the online log: 15:08:02 semget: errno = 28 15:08:02 create_vp: cannot allocate memory When I do a ps -ef | grep oninit, I'm seeing tons of oninit -s processes out there. I'm not a trained dba but the famous "guy who read the manual." We have had a couple of nasty crashes in the last 48 hours, one of which ultimately involved going to backup data and reinitializing Informix. When we attempted to bring Informix online again after the crashes, the error messages were as follows: shmget: [EEXIST][17]: key 52644801: shared memory already exists 09:18:15 mt_shm_init: can't create resident segment My interpretation of this was that something in the engine believed that it already had shared memory, even though it did not, and therefore would no create shared memory. This problem was fixed only by reinitializing. What else should I be looking at? Mark McDonough --

Mark, Engine possibly cannot add additional shared memory (SM) segment. Tune SHMMAX kernel parameter [and maybe Informix parameter SHMTOTAL in your ONCONFIG, if not a 0]. Monitor shared memory segments allocated by Informix by onstat -g seg. Your problem is caused by orphan shared memory segments after crash. What to do : 1. Make sure Informix is not running. 2. Find all shared memory segments left after crash (ipcs -m on most platforms). These fragments should belong to user informix. In your case, the key of ones is 52644801. 3. Remove them with ipcsrm (again, I do not know what the name on IRIX). 4. Try to bring Informix up (if you have decided not to restore from level 0 backup) or start cold restore with onstat -r (in case of using ontape arhives, I know nothing about onbar syntax). If you decide to restore: 5. After level 0 restore (and possibly level 1,2 & logical logs) engine is in quescient mode. Go to online mode to complete restore and fast recovery. 6. See what happens in online.log. Best regards, Sergey