Start of Content Area

Object documentation Asynchronous I/O (Informix)  Locate the document in its SAP Library structure

Definition

Asynchronous I/O (AIO) in the Informix database is performed either by special processes, called AIO virtual processors (AIO VPs), or, when kernel asynchronous I/O (KAIO) is supported by the operating system, by the CPU VPs using KAIO threads. This part of the main screen tells how many of each of these entities are configured.

The database server performs all database I/O asynchronously so that the I/O is queued and performed independently of the thread that requests the I/O. Performing I/O asynchronously allows the thread that makes the request to continue working while the I/O is being performed.

The Files column is simply a count of distinct paths used for the raw devices in the database (normally with the path /informix/SID/sapdata/... ). Informix assumes that these distinct paths refer to separate physical disks, though with LVM and RAID5 this might not in fact be true.

Use

You can use the database overview of the SAP/Informix database monitor to view AIO.

 

See also:

NUMAIOVPS (Informix)