Tag Archives: smart scan

Changing attributes on ASM Diskgroups

You can see the attributes set on your ASM diskgroups in 2 ways, via the view  v$asm_attribute

SQL> select a.name, b.name, b.value from v$asm_attribute b, v$asm_diskgroup a where a.group_number=b.group_number and a.name='DATAX6C1' ;

Or via asmcmd and the lsattr

grid@sc7ach00pd00-d1:~$ asmcmd

ASMCMD> cd DATAX6C1
ASMCMD> lsattr -G DATAXC1 -l

Attributes you might want to pay attention to in an Exadata environment are

  • compatible.advm
  • cell.smart_scan_capable
  • appliance.mode
  • compatible.asm
  • compatible.rdbms

If you manually create a diskgroup via asmca these attributes will not normally be set, and so you may want to go manually set them.

SQL> ALTER DISKGROUP DATAX6C1 SET ATTRIBUTE 'appliance.mode'='TRUE';

The attribute is set immediately, but based on my experience, it does not come into effect until the disk group has  been rebalanced.

SQL> alter diskgroup DATAX6C1 rebalance power 2;
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