Using Oracle with CTE-U
When guarding an ASM disk with CipherTrust Transparent Encryption UserSpace, there can be a change in database performance. This occurs when the underlying device is in Oracle direct mode. This mode avoids double-caching, which consumes memory, and therefore impacts performance on some workloads.
This issue is affected by the block_o_direct
parameter. If that parameter is set to 0
, the IO will be reported as complete, (meaning committed to disk) before it actually is. This is a data integrity risk for a database, because the normal mode is to mark as journal complete as soon as the data is safe on a disk. This incorrect reporting could result in a race that could lead to a journal being cleared before the data is on the disk. If a crash occurs during this window, the data would be lost.
In this scenario, data integrity and performance are at odds. You must choose which one to highlight.
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To set CTE-U for optimal data integrity, type the following command:
voradmin secfs config block_o_direct 1
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To set CTE-U for optimal performance, type the following command:
voradmin secfs config block_o_direct 0
Note
The commands listed in the steps above will change the block_o_direct
parameter in CipherTrust Transparent Encryption UserSpace, in the config.yaml
file located in: /opt/vormetric/DataSecurityExpert/agent/secfs/.sec/conf/secfs_config.yaml