Pythian Blog: Technical Track

ORA-15418: appliance mode not supported for compatible.asm 12.1.0.0.0

by Fred Denis on Jul 20, 2016 12:00:00 AM

The other day, I was upgrading a compatible.asm parameter to 12.1 on Exadata and I faced this error for the first time : https://gist.github.com/freddenis/b23a0da5d6e493255d2636c7008d431a Indeed, a diskgroup can have this parameter set to TRUE or FALSE : https://gist.github.com/freddenis/3e6e9474d2f1b937f3c942676ab277b7 I then found this note on Metalink : EXADATA : What Is Oracle ASM appliance.mode Attribute (Doc ID 1664261.1) which explains that starting from Exadata 11.2.0.3.3, " The Oracle ASM appliance.mode attribute improves disk rebalance completion time when dropping one or more Oracle ASM disks. This means that redundancy is restored faster after a failure." Wow, that looks like a pretty cool feature! But it seems that (sadly) we cannot set a 12.1 compatible if this feature is enabled. Let's give it a try and deactivate it to set my compatible.asm to 12.1 : https://gist.github.com/freddenis/12c392d55b9088bb144bc1fde56d826e It works ! Now that this compatible.asm is set to 12.1, could we enable that appliance.mode feature again ? https://gist.github.com/freddenis/7ae8c3d5f5dedc4feabd11f3f09f8ce8 Sadly, no. I hit one of the restrictions; indeed, " The Oracle ASM disk group attribute compatible.asm is set to release 11.2.0.4, 12.1.0.2 and later. (Appliance mode is not valid with 12.1.0.1)" -- then I guess that even of the documentation does not say so, Appliance mode is not valid with a compatible.asm set to 12.1.0.0.0 either. Even if it is very weird that Oracle dev "forgot" (?) this cool feature when they released 12c on Exadata, they hopefully "released" it again with 12.1.0.2. I'll follow up on that when moving this compatible.asm to 12.1.0.2 !
Topics: Oracle Performance Technical Track 12C Stefan Knecht Dynamic Sampling

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