Re: Recovering database from crashed HD (bad sectors)

On Sat, Jul 18, 2015 at 6:59 PM, Amitabh Kant <amitabhkant(at)gmail(dot)com> wrote:
> A development box hard disk failed which was running a PG instance with
> multiple databases on it. I got the data recovered with some bad sector
> errors. Ran another instance of PG (same version), and was to able to take
> dump (using pg_dump) of all but one database. For one database I am getting
> the following error:
>
> pg_dump -Fc alpha_45 > alpha_45.dump
> pg_dump: [archiver (db)] connection to database "alpha_45" failed: FATAL:
> could not open file "base/525035/11678": No such file or directory
>
> These are the only two files in the directory similar to the one above:
> /usr/local/pgsql/data/base/525035/11678_fsm
> /usr/local/pgsql/data/base/525035/11678_vm
>
> Is there any hope of recovering this DB, or should I start looking into
> restoring from old backups? Data loss is not a concern, I just would like to
> know if I should even try working on it. I looked into this page
> http://www.postgresql.org/docs/9.1/static/runtime-config-developer.html, and
> tried using "zero_damaged_pages = on" in postgresql.conf, but it was of no
> help.

Visibly your data is already lost in alpha_45... Hence if you can
recover this database from an older backup you had better do it. Now
perhaps other folks here have other recommendations and strategies
though :)
--
Michael