Chunks down after upgrade (4.1 -> 5.0)

Hi there, After a number of successful upgrades from 4.1 to 5.0 we have encountered a problem when trying to bring informix online after upgrading one of our installations. On this specific installation we have our Dbspaces and chunks configured as follows: Dbspaces address number flags fchunk nchunks flags owner name c0075cac 1 1 1 2 N informix rootdbs c0075cdc 2 1 2 1 N informix logdbs c0075d3c 4 1 5 1 N informix dbs3 c0075d6c 5 1 6 1 N informix dbs4 4 active, 8 total Chunks address chk/dbs offset size free bpages flags pathname c007532c 1 1 0 150000 34037 PO- /dev/rdsk/4s0 c00753c4 2 2 0 50000 16992 PO- /dev/rdsk/5s0 c007545c 3 1 150000 125000 99997 PO- /dev/rdsk/4s0 c007558c 5 4 0 225000 115894 PD- /dev/rdsk/rawdisk5 c0075624 6 5 0 225000 119214 PD- /dev/rdsk/rawdisk6 5 active, 8 total Dbspace 4 an 5 (with correspnding chunks 5 and 6) cannot be opened. The error can be seen in the turbolog like: 15:53:40 I/O read() chunk 5, pagenum 4, pagecnt 1 --> errno = 22 15:53:40 tblspace header error: ...<dump> 15:53:40 -- Fail Consistency Check -- pthdrpage:ptalloc:bad bfget -- pid=17744 user=201 us=c04f20e8 15:53:40 Cannot Open Dbspace 4 The same message also applies to Dbspace 5. When we rolled back to version 4.1, we could bring Informix online without any error messages, but the chunks were still down according to tbstat -d. The most peculiar thing about it is that now we can access the Dbspaces although the chunks are marked as down! We browsed through the earlier messages but couldn't find any indication that Informix have had any problems with these Dbspaces. The installation is running on HP 9000/730 HP-UX 8.05. 1) What happened? 2) Howcome we can read the Dbspaces when the chunks are down? 3) If we reinitialize the chunks : Can we restore a 4.1-backup when running 5.0? Any anwers appreciated Lars Fransson (lars@paxutv2.ostra.se) Sandro Borghesi (sabo@paxutv2.ostra.se) MIB Ostra Sjukhuset Gothenburg