SAP recommends, in heavily used databases, that you distribute data across multiple disks. To do this effectively, you must monitor disk usage.
If one or more disks are consistently very busy, distribute the database objects on those disks to other devices. This strategy spreads out the work among disks and allow for greater data throughput.
To determine which devices a specific database is using, run sp_helpdevice or sp_helpdb.
For more information, see sp_helpdevice and sp_helpdb in the Reference Manual: Procedures; also see the System Administration Guide: Volume 2.
To check for disk space usage rates and I/O contention, run sp_sysmon.
For more information, see sp_sysmon in the Reference Manual: Procedures; see also the Performance and Tuning Series: Monitoring SAP ASE with sp_sysmon.