Error 823

Severity

24

Message text

I/O error detected during %S_MSG for %S_BUF.

Explanation

This error occurs when Adaptive Server encounters an I/O error on a read or write request made to a Sybase device. It usually means you have disk problems. The parameters in the error message refer to internal Sybase structures and do not often help determine which device is involved. However, additional kernel messages in Adaptive Server’s error log recorded before the 823 error was raised should indicate which device is involved.

Causes of the 823 error can include the following:

• If the sum of vstart and size exceeds the device size. This can happen on AIX systems but is also possible on other UNIX platforms if sysusages or sysdevices have been manually altered.

• When using UNIX files as devices, if the file system is full but the device appears to have space as tracked by sysusages and sysdevices. This raises the 823 error during create database or alter database.

Action

Check the accessibility and condition of the device in question. Once you have identified and corrected the problem, execute the dbcc checkdb and dbcc checkalloc commands to ensure that no other damage was caused by the bad device.

Error 823 may occur if the disk device is run under the logical volume manager (LVM), vstart is equal to 2 and the size is not shortened by 2. vstart needs to be equal to 2 because the first AIX block (1 AIX block equals 2 Sybase pages) has to be available for the LVM control block (LVCB).