Why Asynchronous IO:
Undesired synchronous I/O can have a major impact on the HANA performance, especially restart time and table load time for read I/O as well as savepoint and write transaction commit times for write I/O.
HANA uses asynchronous IO to write to and read from disk. Ideally, asynchronous IO should have a trigger ratio close to zero. A trigger ratio close to 1 indicates asynchronous IO that behaves almost like synchronous IO, that is: triggering an IO request takes just as long as executing it and hence very prone to performance degradation of HANA system. In such cases we need to activate asynchronous IO for a particular file system/path.
Undesired synchronous I/O can have a major impact on the HANA performance, especially restart time and table load time for read I/O as well as savepoint and write transaction commit times for write I/O.
HANA uses asynchronous IO to write to and read from disk. Ideally, asynchronous IO should have a trigger ratio close to zero. A trigger ratio close to 1 indicates asynchronous IO that behaves almost like synchronous IO, that is: triggering an IO request takes just as long as executing it and hence very prone to performance degradation of HANA system. In such cases we need to activate asynchronous IO for a particular file system/path.
