Enabling Concurrent I/O


Enabling Concurrent I/O
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Because you do not need to extend name spaces and present the files as devices, you can enable Concurrent I/O on regular files.

Warning:

If you use the -o cio option with the mount command to mount your primary database file systems, the Concurrent I/O settings will not be preserved when using Database FlashSnap commands or the db2ed_clonedb command.

Before enabling Concurrent I/O, review the following information:

Prerequisites

To use the Concurrent I/O feature, the file system must be a VxFS file system.
Make sure the mount point on which you plan to mount the file system exists.
Make sure the DBA can access the mount point.

Usage notes

Files that are open and using Concurrent I/O cannot be opened simultaneously by a different user not using the Concurrent I/O feature.
Veritas NetBackup cannot backup a database file if the file is open and using Concurrent I/O. However, you can still backup the database online using the utility.
When a file system is mounted with the Concurrent I/O option, do not enable Quick I/O. DB2 will not be able to open the Quick I/O files and the instance start up will fail. Quick I/O is not available on Linux.
If the Quick I/O feature is availabe, do not use any Quick I/O tools if the database is using Concurrent I/O.
See the mount_vxfs(1M) manual page for more information about mount settings.