Balancing I/O

Balancing I/O on your system. It explains how to use disk striping and how to locate files on separate disks to gain better performance. Controlling the size of the message log file is also discussed.

• Raw I/O (on UNIX Operating Systems)
  You can create a database or dbspace on a raw device or a file system file.
• Using Disk Striping
  Disk striping is a generic method of spreading data from a single file across multiple disk drives. Striped disks achieve significant performance gains over single disks.
• Internal Striping
  Disk striping lets you take advantage of multiple disk spindles at once, and provides the speed of parallel disk writes.
• Using Multiple Files
  Using multiple files in a dbspace allows your Sybase IQ and temporary data to be distributed across multiple operating system files or partitions. Multiple files improve throughput and reduce average latency for the dbspace.
• Strategic File Locations
  Provide additional storage resources to improve random and sequential file disk I/O.
• Working Space for Inserting, Deleting, and Synchronizing
  When you insert or delete data, and when you synchronize join indexes, Sybase IQ needs some working space in the IQstore. This space is reclaimed for other purposes when the transaction that needs it commits.
• Setting Reserved Space Options
  Two database options, MAIN_RESERVED_DBSPACE_MB and TEMP_RESERVED_DBSPACE_MB, control the amount of space Sybase IQ reserves for certain operations.