Oracle ZFSSA Storage Appliance – disabling SNMP service kills the Hybrid Comlumnar Compression functionality

In a customer project, we are running several ZS7-2 Oracle ZFS Storage Appliances ZFSSA in bundled with Private Cloud Appliances PCA. The ZFSSA is a very powerful storage solution with a lot of functionality like OISP (Oracle Intelligent Storage Protocol), or – when an ADVANCED COMPRESSION license is yours – Hybrid Columnar Compression HCC.

But once in a day when I tried to create a Hybrid Columnar Compression enabled tablespace in a 19c pluggable database in our test system, I got this error:

ORA-64307: Exadata Hybrid Columnar Compression is not supported for tablespaces on this storage type

Investigation

This was easy, the MOS document Exadata Hybrid Columnar Compression” Is Not Working in Exadata Using ZFS Storage Appliance (ZFSSA) and Failing with [ORA-64307: Exadata Hybrid Columnar Compression is not Supported for Tablespaces on This Storage Type] (Doc ID 2393108.1)  mentions, to check if the SNMP service on ZFSSA is enabled.A dNFS issue could be excluded very fast, because regular uncompressed tablespaces could be created.

And here we go: ZFSSA BUI – Configuration – Services: DISABLED 🙁

You can check the ZFSSA SNMP functionality by a snmpget command, executed on the database server:

FYI: The IP address of the ZFSSA exports are stored  in $ORACLE_HOME/dbs/oranfstab.

So let’s enable it and see what’s happen now.

The command snmpget shows the ZFSSA enabled service now and gives us a feedback.

Test 1 – Create HCC enabled Tablespace after SNMP restart

Another try, same error. Only to enable the service on ZFSSA has no effect.

We restart the database instance.

Test 2 – Create HCC enabled Tablespace after SNMP and Database Instance restart

Verification:

What’s happen

During a database instance startup, there is a check to verify if a ZFSSA with enabled SNMP is available. This is visible in the alertlog:

And once the database instance has recognized it, HCC enabled tablespaces and tables are allowed. Even when you stop the SNMP service now, HCC can be used. Only when the database instance is restarted again, there is no such entry in the alertlog. Which means: no HCC.

Summary

The ZFS Storage Appliance SNMP service is essential to benefit of the hybrid Columnar Compression feature. Never disable it. Ok, now you ask yourself: why this service was disabled? It was a simple mistake of mine during a support case analysis… MOS recommended to disable the SMTP service. And as you can see, the SMTP service is above SNMP service.

Or in Bart Simpson’s style: