Hello all,
If I were in your situation, I would analyze if it could move only a part
of the 36 databases to the new disk.
* Either, I will move some of the databases to the new disk,
* Either, In the largest databases, I will consider to work in multiple
tablespace configuration, using the command ALTER TABLE <<TableName>> SET
TABLESPACE <<TablespaceName>>; Link to the documentation:
https://www.postgresql.org/docs/9.6/sql-altertable.html . to move some
tables to the new disk. You can analyze (depending on your disk and DB
configurations, if it's better to move the very large tables or
intensively used tables.
I hope I'm clear enough!
Feel free to ask for clarification or add new elements to go further on!
Hope this helps,
Have a nice day,
Thomas
Le mer. 20 févr. 2019 à 21:37, Ron <ronljohnso...@gmail.com
<mailto:ronljohnso...@gmail.com>> a écrit :
On 2/19/19 5:02 PM, Julie Nishimura wrote:
Hello, we are almost out of space on our main data directory, and
about to introduce new directory to our cluster. We cannot use
multiple physical disks as a single volume, so we are thinking about
creation new tablespace.
Our current data_directory shows as follows:
/data/postgresql/9.6/main
postgres=# SELECT spcname FROM pg_tablespace;
spcname
------------
pg_default
pg_global
(2 rows)
We also have 36 existing databases on this cluster.
If we add new directory, will it be enough to execute the following
commands in order to force new data there:
CREATE TABLESPACE tablespace01 LOCATION '/data/postgresql/9.6/main01';
ALTER DATABASE db_name SET TABLESPACE
tablespace01
Do I need to repeat it for all our existing databases?
Since the command is ALTER DATABASE <your_user_db>, it seems that yes
you have to do it for all of them. A simple bash script should knock
that out quickly.
Should I change our "template*" dbs as well?
If you want *new* databases to automatically go to tablespace01 then
alter template1.
Do I need to do something else?
Maybe, depending on the size of your databases, and how much down
time you can afford,
https://www.postgresql.org/docs/9.6/sql-alterdatabase.html "This
command physically moves any tables or indexes in the database's old
default tablespace to the new tablespace."
For example, our multi-TB databases are so big that moving it all at
once is unreasonably slow. And a failure might leave the db is a bad
spot. Thus, I'd move one table at a time, a few per outage.
Naturally, YMMV.
Thank you for your advises.
--
Angular momentum makes the world go 'round.
