DMS replication task reducing the free storage in rds postgres .

Question

HI,

I  have a dms replication task to  replicate tables from one rds postgres instance to another. I  have  created  a scheduler to  run  the  replication task  for every 6  hour and  stop after 30  mins. At the time of  stopped state the free disk space in rds is drastically  decreasing (in  1  hr  12 GB to  6) .  I have  set  logical_replication =1 for  source  rds  instance. Please  help to  understand  why this  much storage  is  utilized for  logging? Is there  a way  to  limit this  usage ?

Didier_Durand · Answer

Hi,

The volume of disk is related to the size of the update log, corresponding to the activity on your database.

So, you should first measure the size of update log on your to pg to evaluate if the disk space is in proper relation with it or not. Such a request should give you the size of all logs:

```
SELECT sum(stat.size)
FROM pg_ls_dir(current_setting('log_directory')) AS logs
   CROSS JOIN LATERAL
      pg_stat_file(current_setting('log_directory') || '/' || logs) AS stat;
```

Note: is there a reason why DMS replication isn't permanently on? That would reduce its disk storage on source machine drastically.

Best,

Didier

DMS replication task reducing the free storage in rds postgres .

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