Обсуждение: Upgrading from 7.2.4 (RH 8) to 7.4 (RH9)

Hi,

I would like to start planning on upgrading a few servers from RH8 to RH9, essentially, also upgrading Postgres from 7.3.2 to 7.4 from the OS.

There's also a box with RH7.3 (postgres 7.2.1) that could be upgraded to RH9 and Postgres 7.4.

I am not sure if I should backup (pg_dump) the databases, and do a clean install of the OS, and do a pg_restore…OR, just upgrade the OS..?

Are there any issues that I should be aware of?

Any relevant procedure that can come handy?

Thanks,
Anjan

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I would like to start planning on upgrading a few servers from RH8 to RH9, essentially, also upgrading Postgres from 7.3.2 to 7.4 from the OS.

There's also a box with RH7.3 (postgres 7.2.1) that could be upgraded to RH9 and Postgres 7.4.

I am not sure if I should backup (pg_dump) the databases, and do a clean install of the OS, and do a pg_restore…OR, just upgrade the OS..? This is what I do when migrating .
1. Take a file system backup of  PostgreSQL "data"   folder  preferably with DUMP
2.  Take a back up of   data  with
        pg_dump --disable-triggers -U <USER NAME>  -a -d -b -D -Fc -Z 9  -f    filename.tar.gz   <DATABASE NAME>
       a. This will take care of blobs (Though 7.2 does not have it)
       b. Make sure that your data be less than 8 GB as tar could not handle  more than that
3.  Yes Schema is also required to be backed up with above command and having switch as

        pg_dump --disable-triggers -U <USER NAME>  -s Fp  -f    schema.sql   <DATABASE NAME>
4. Now why Schema is dumped separately to that of  data
    Because :
    a. pg_dump will dump the schema as per its own wish and not as per the  database requirement so
       if a required user defined function is not  in the secema dump as early as it is required  your pg_restore will
       abort with Xmas bells
    b. In this case you can rearrange the creation of  Schema as
          Create functions > then table >  then sequences > then views
5.  Now after all stuff you have done install your new OS
    initdb  a new database in the same directory location as it was in the old one (i.e in the older OS)
6. Now try restore the Schema  if succeeds  then go to 7 else
    rearrange your sql statements to satisfy the monster
7. Restore Data with
    pg_restore  --disable-triggers -U <USER NAME>  -d   <DATABASE NAME>  ./filename.tar.gz
8. Now if 6 and  7 fails you have a chance reinstall the older version of postgresql and also its DUMP file to regain the data and schema again and start again from point 2 to 8
  
This is what I do  to restore / migrate and have got 100 % results till date

Any one having a better and more reliable method please pass it on to  Anjan Dave and me

We would be grateful to you

Regrads,
V Kashyap