Procedure for fixing and repair multiple instances

Hello,

Please refresh my memory,

I have four instances, configured :

Server AAAA /db1 instance 1 instance 2
/db2 instance 3 instance 4

Postgresql 9.3 running on Debian 7,

My disk array failed and recovered itself, all disk partitions mounted ok,
but i have to run fsck in /db1 and /db2,
I could manually start instance 1 whitout message errors, but instance 2
announces:

/db1/postgresq9.3/cal/ is not a valid data directory
file /db1/postgresql9.3/cal/PG_VERSION does not exist

So Instance 1 started ok but Instance 2 does not start, how I fix this
error ? I try to re-create this file manually but later mention to
PG_CONTROL does not exist started to appear, this give me the idea that
some kind of corruption damaged this directory.

Am I comdenmed to re-install again ???
What could be the best method without touching the instance that is working
ok ?

Instance 3 and Instance 4 started ok but several messages like this:

Statistics file pg_stat_tmp/db_12034.stat is corrupted

in their respective log files,

During the fsck processs for /db2 I could see several messages like,
specially during phase 2 check directory structure:

ENTRY 'dbo.stat' which is in /postgresql/9.3/qa/pg_stat_tmp has a
incorrect file type (it was 1 but should be 2) Fix(y) ?

if this is related, how I could clean this messages or fix it ?

Thanks a lot

Any idea or recommendation is welcome