48 out of 58 chunks down

This is a plea for urgent help with a failure of one of our Informix instances. My company runs on an Informix software package, using Online 5.03, which we have been upgrading over the weekend. Because the upgrade involved many "alter table" statements, we archived, ran the upgrade without logging, then attempted to re-archive and restart logging. At this point, Informix decided to mark 48 out of 58 unmirrored chunks as "down". In fact, the chunks are mirrored in hardware, and are all OK from a UNIX point of view (mode=660 u=informix g=informix, too, before you ask). Chunks 1 to 10 are OK, chunks 11 to 58 are all down. That seems too neat: there must be some reason for the pattern. As I understand it, what we need to do is correct the problem which is preventing Informix from accessing the chunks, then restore from the last archive, which is the only supported means of recovering from a non-mirrored chunk down. But we can't see any reason why the chunks (most of which worked fine before the upgrade) are not useable. Can anyone help? We have contacted Informix (and agreed to pay them), but have heard nothing back from them yet. The critical part of the message log reads (manually transcribed):- I/O read() chunk 11, pagenum 4, pagecnt 1 --> errno = 22 tblspace header error: de8958: 00000000 00000000 00000000 00000000 de8968: 01000000 0100000b 0400b000 00000000 (13 lines of zeroes omitted) de8a48: 00000000 182e0601 ed09a046 00000000 de8a48: 588e1001 X... -- Fail Consistency Check -- pthdrpage:ptalloc:bad bfget -- pid=1234 user=102 us=401bc0 Cannot Open Dbspace 11 This is all repeated 47 more times. Please copy any reply to "chris.webb@theso.co.uk". Thanks to anyone who can help. Please excuse the use of bandwidth, but we are pretty desperate. -- Peter R Wotherspoon