HADB File System Support

There are several important considerations if you want to configure HADB to use one of the following file systems:

• ext2 and ext3 — HADB supports ext2 and ext3 file systems for Red Hat Application Server 3.0. For Red Hat Application Server 2.1, HADB supports only the ext2 file system.

• Veritas– When the Veritas File System is used on the Solaris platform, the message WRN: Direct disk I/O mapping failed is written to the history files. This message indicates that HADB cannot turn on direct I/O for the data and log devices. Direct I/O is a performance enhancement that reduces the CPU cost of writing disk pages. It also causes less overhead of administering dirty data pages in the operating system.

  To use direct I/O with the Veritas File System, use one of the following:

  • Create the data and log devices on a file system that is mounted with the option mincache=direct. This option applies to all files created on the file system. See the mount_vxfs(1M) command for details.

  • Use the Veritas Quick I/O facility to perform raw I/O to file system files. See the VERITAS File System 4.0 Administrator's Guide for Solaris for details.

    Note that these configurations have not been tested with Application Server 8.1 2005Q2 Update 2.

    Refer to the Application Server Enterprise Edition High Availability Administration Guide for information about installing and configuring HADB with Application Server software.