Re: running out of disk space

[Julie Nishimura <juliezain@xxxxxxxxxxx>]

Alan, thanks for your reply.

So, we currently have this situation:

/dev/sda1             2.7T  2.4T  298G  90% /data/vol1

/dev/sdb2             2.7T  2.4T  296G  89% /data/vol2

/dev/mapper/vg00-data

                       16T   16T  373G  98% /data/vol3

postgres=# SELECT * FROM pg_tablespace;

  spcname   | spcowner | spclocation |              spcacl              

------------+----------+-------------+-----------------------------------

 pg_default |       10 |             |

 pg_global  |       10 |             |

 vol1       |       10 | /data/vol1  | {postgres=C/postgres,=C/postgres}

 vol2       |       10 | /data/vol2  | {postgres=C/postgres,=C/postgres}

 vol3       |       10 | /data/vol3  | {postgres=C/postgres,=C/postgres}

(5 rows)

And we added new volume yday:

/dev/mapper/vg00-vol4
                      4.0T  195M  3.8T   1% /data/vol4

So, if I understood you correctly, it is better to extend vol3 instead of creating new tablespace on vol4 (if possible).

If not, then what is my best bet?

Thanks,

Julie

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From: Alan Hodgson <ahodgson@xxxxxxxxxxxxxxx>
Sent: Thursday, May 9, 2019 9:15 AM
To: Julie Nishimura; pgsql-general
Subject: Re: running out of disk space

 

On Thu, 2019-05-09 at 15:46 +0000, Julie Nishimura wrote:

hello,

We are running out of disk space, and we introduced new volume to it. I am about to create new tablespace X and alter user databases to set to this new tablespace X. So, all new tables will be created in X, but what about existing tables on previous volume? Its data will be split between 2 tbspaces?

Please clarify. Thank you!

Tables and indexes can only be on one tablespace. You'll need to individually move them with alter table and alter index. They will be locked while being moved. You should experiment with this on a test server to learn how it works.

However, unless your new volume has different I/O characteristics than the existing volume you really shouldn't use tablespaces. You should use your OS volume manager and filesystem tools to extend the data volume and filesystem into the new space. This will be much easier to manage. I'm sure your system administrator can assist you with this.