Hello Stephane, I assume that your database has good non-corrupted metadata, so you just need to buy FBDataGuard and export all available records from tables with problems (using re-export of metadata), then merge good data from corrupted database and exported records into new healthy database.
Regards, Alexey Kovyazin IBSurgeon > Hello, > > On our database (FB 2.5) of 150 GB we have 21 bad sectors of 512 bytes (all > in the same block). because of that the backup/restore not work (even with > the -ignore option). And gfix not help us too much because it's freeze and > crash the fb_inet_server (but it's was also the case before the bad sectors > problem, so it's a bug in gfix i guess). > > Now i need to know with table/records are involved in the 21 bad sectors and > how to delete them. I already locate one table involved (and successfully > drop it, it's was not a very important table), but their is also another > table involved that i need and can't drop it. so i locate exactly the record > ID in error (by doing select until error appear) and try to delete them but > without success because engine answer me : > Statement failed, SQLSTATE = XX001 > database file appears corrupt () > -bad checksum > -checksum error on database page 7456994 > > what are now my option ? > > i thing of manually update the checksum (by 12345) on the database page > 7456994 (and the page type too), but i hope their is a more convenient way > than hex edit my database ? > > another problem from reading Ann articles : > "Here's the full scoop on checksums. Once upon a > time, in a cute little town called Groton, there was a database and > to be extra safe, it computed a checksum of every page just before > it wrote the page to disk,and wrote the checksum in the page header. > Immediately after it read the page, it computed the checksum again, > and if the stored checksum didn't match the computed checksum it > produced an error. The error almost never occurred, and when it did occur, > the stored checksum was zero, and so was every other byte on the page. Then > the database moved to a lovely town in California called Santa Cruz, where it > had different friends who took care of it. Those friends were looking for > ways to make the database faster and their tests showed that the database was > spending a lot of time (5-10%) computing checksums. So, they said, OK, 12345 > is different from zero, so we'll still catch the same errors, but we won't > waste time computing something that never fails." > > it's mean that engine report error only if the checksums is different from > 12345 (and i imagine the checksums is written only on the page header not on > every disk sector of 512 bytes). as my page header is 8kb and my bad sectors > is only 512 bytes, what happen if the page header is not on a bad sector (so > page will return good checksum) BUT the the page content contain bad sector ?? > > thanks by advance > stéphane > >
