1.180 MAX_IOPS

MAX_IOPS enables you to set the maximum number of I/Os that can be issued per second on a per pluggable database (PDB) basis. This parameter is used to throttle PDB I/Os.
Property Description

Parameter type


Default value




Modifiable in a PDB


Range of values

0 to the maximum Integer value. A very low value (for example, under 100 I/Os per second) is not recommended.



Oracle RAC

Different values can be set on different instances.

DBWR I/Os, control file I/Os, password file I/Os and other critical I/Os are exempted from the rate limit set by this parameter, but their I/Os are accounted for while throttling. Because of these exemptions, the PDB's actual I/O rate may sometimes exceed the limit.

This feature is enabled for multitenant container database (CDB) only. The feature is not supported on Oracle Exadata.

This parameter can be set from inside a PDB. If the parameter is set in CDB$ROOT, all the PDBs in that CDB will inherit the parameter value from CDB$ROOT. This parameter cannot be set in a non-CDB environment.

The default value of 0 means that no limits are set on the maximum number of I/Os that can be issued per second in a PDB.

If Oracle processes need to wait because of this IO rate limit, the wait event is resmgr: I/O rate limit.


This initialization parameter is available starting with Oracle Database 12c Release 2 (


This example shows how to use SQL statements to set a maximum of 3000 I/Os per second on a PDB named CDB1_PDB1:

alter session set container = cdb1_pdb1;
alter system set max_iops = 3000;