Sybase Devices Test

This test, executed by an internal agent, tracks statistics pertaining to the devices of the Sybase adaptive server.

Target of the test : A Sybase ASE (Below v15) server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Sybase ASE (Below v15) server being monitored

Configurable parameters for the test
Parameter	Description
Test Period	How often should the test be executed.
Host	Refers to the IP address of the Sybase server.
Port	The port number at which the Sybase server listens to.
User	A Sybase user who has the “sa_role”.
Password	The password corresponding to the above user.
Confirm Password	Confirm the password by retyping it here.

Measurements made by the test
Measurement	Description	Measurement Unit	Interpretation
I/O requests	The average number of IO requests for a device	IOs/Sec
Physical reads	The average number of reads performed on a device	Reads/Sec
Physical writes	The average number of writes performed on a device	Writes/Sec
I/O errors	The percentage of times there was an error in IO requests	Percent
I/O waits	The percentage of times the semaphore was busy and the IO operation had to wait for the semaphore to be released	Percent	When Adaptive Server needs to perform a disk I/O, it gives the task the semaphore for that device in order to acquire a block I/O structure. On SMP systems, multiple engines can try to post I/Os to the same device simultaneously. This creates contention for that semaphore, especially if there are hot devices or if the data is not well distributed across devices. A large value could indicate a semaphore contention issue. One solution might be to redistribute the data on the physical devices.