Not too many features to talk on 19c ASM. Below is my hand-pick features of 19c ASM for this blog post.
Automatic block corruption recovery
With Oracle 19c, the CONTENT.CHECK disk group attribute on Exadata and cloud environment is set to true by default. During data copy operation, if Oracle ASM relocation process detects block corruption, it perform automatic block corruption recovery by replacing the corrupted blocks with an uncorrupted mirror copy, if one is avialble.
Parity Protected Files Support
The level of data mirroring is controlled through ASM disk group REDUNDANCY attribute. When a two or three way of ASM mirroring is configured to a disk group to store write-once files, like archived logs and backup sets, a great way of space is wasted. To reduce the storage overahead to such file types, ASM now introduced PARITY value with REDUNDANCY file type property. The PARITY value specifies single parity for redundancy. Set the REDUNDANCY settings to PARITY to enable this feature.
The redundancy of a file can be modified after its creation. When the property is changed from HIGH, NORMAL or UNPROTECTED to PARITY, only the files created after this change will have impact, while the existing files doesn't have any impact.
A few enhancements are done in Oracle ACFS, Oracle ADVM and ACFS replication. Refer 19c ASM new features for more details.
** Leaf nodes are de-supported as part of Oracle Flex Cluster architecture from 19c.
Automatic block corruption recovery
With Oracle 19c, the CONTENT.CHECK disk group attribute on Exadata and cloud environment is set to true by default. During data copy operation, if Oracle ASM relocation process detects block corruption, it perform automatic block corruption recovery by replacing the corrupted blocks with an uncorrupted mirror copy, if one is avialble.
Parity Protected Files Support
The level of data mirroring is controlled through ASM disk group REDUNDANCY attribute. When a two or three way of ASM mirroring is configured to a disk group to store write-once files, like archived logs and backup sets, a great way of space is wasted. To reduce the storage overahead to such file types, ASM now introduced PARITY value with REDUNDANCY file type property. The PARITY value specifies single parity for redundancy. Set the REDUNDANCY settings to PARITY to enable this feature.
The redundancy of a file can be modified after its creation. When the property is changed from HIGH, NORMAL or UNPROTECTED to PARITY, only the files created after this change will have impact, while the existing files doesn't have any impact.
A few enhancements are done in Oracle ACFS, Oracle ADVM and ACFS replication. Refer 19c ASM new features for more details.
** Leaf nodes are de-supported as part of Oracle Flex Cluster architecture from 19c.
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