About ACFS filesystem
ACFS mean Automatic Storage Management Cluster File System. This filesystem volume resides inside the ASM database and can be used to store database files but also any type of files with or without direct relation to the database.
Oracle ACFS does not support Oracle Grid Infrastructure or Oracle Cluster Registry voting files.
The ACFS filesystem can be extended dynamically without any service interruption, you just need to add space to the diskgroup hosting the ACFS volume and then extend the filesystem. Continue reading Creating an ACFS filesystem
I recently came across an issue while exporting a huge partitioned table for a data migration. The export took years without any obvious reason.
After some research I found that the parallelism wasn’t working, I could only see one datapump worker at a time, then I found this note explaining the behaviour (Doc ID 1467662.1) .
A table with BASICFILE lobs cannot be exported in parallel, oracle advise to convert those BASICFILES to SECUREFILES; this was not possible for me.
The second solution was to run multiple export jobs in parallel, each one exporting a fraction of the table rows. In the example, oracle use a query using a range of the primary key to do an export, this was ok but I needed a more automatic method to divide the rows based on the degree of parallelism I wanted to apply, then I found this blog post from Morten Jensen.
Continue reading Datapump in parallel with a shell script
It can be quite useful to be able to monitor long running operations on your database, the view v$session_longops can be used to estimate the time necessary for certain operations to finish. Continue reading Monitoring long running operations