We are currently running postgres 9.4.8 after a successful upgrade from 9.2 using pg_upgrade with the link option. The OS we are running is GNU/linux 2.6.32
As you know the link option 'hard links' the data from the old 9.2 cluster with the data in the new 9.4 cluster. The pg_upgrade documentation states that
Once you are satisfied with the upgrade, you can delete the old cluster's data directories
I wish to do this but would like a little more info on 'hard links' before I take this plunge as management would not be too happy with me if I brought down the production db inadvertantly by deleting a cluster.
Here are some checks I ran:
1. ps -ef | grep PSQL_92 (the name of the old cluster) - NOTHING running bearing that literal
2. ls -la /PSQL_92/base/2333 (2333 being the internal name of our major database) - here I see timestamps indicating continual updates of these files (or links):
total 450170748
-rw------- 2 pguser domain^users 438697984 Sep 12 14:05 3908812127
-rw------- 2 pguser domain^users 386875392 Sep 12 14:05 3908824045
-rw------- 2 pguser domain^users 1073741824 Sep 12 14:05 3902046423.1
-rw------- 2 pguser domain^users 503169024 Sep 12 14:05 3902046423.2
-rw------- 2 pguser domain^users 389545984 Sep 12 14:05 3908826153
-rw------- 2 pguser domain^users 1073741824 Sep 12 14:05 797397598.5
-rw------- 2 pguser domain^users 716791808 Sep 12 14:05 3908829834
-rw------- 2 pguser domain^users 716570624 Sep 12 14:05 3908829432
-rw------- 2 pguser domain^users 553828352 Sep 12 14:05 3908828838.3
-rw------- 2 pguser domain^users 210337792 Sep 12 14:05 3908805062
-rw------- 2 pguser domain^users 416833536 Sep 12 14:05 3592193706.2
-rw------- 2 pguser domain^users 1073741824 Sep 12 14:04 8162449.43
This gives me pause. This statement was run on Sept 12 at 14:06. How do I know that if I delete these files that I won't bring down the db?
Another thing I want to share: We were using user-defined tablespaces that were pointing to the 9.2 cluster during the upgrade. I needed to move the objects in that tablespace to the new 9.4 cluster which I have since done.
Any insight appreciated. Thank you,
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