MAX_DBSLICES

onconfig.std
value

0

units

Number of dbslices

range of values

0 through 2047

takes effect

When shared memory is initialized

refer to

Chapter on managing disk space in the IBM Informix: Administrator's Guide

MAX_DBSLICES allows you to increase the maximum number of dbslices to 2047. The safewrite area in the first chunk of the root dbspace grows to accommodate the new maximum number of dbslices. If you set the MAX_DBSLICES value and later decrease it, the database server ignores the new value and uses the previously set value. However, you can increase the MAX_DBSLICES value at any time.

The database server ignores the MAX_DBSLICES value if it is smaller than the number of dbslices that the CONFIGSIZE parameter allows. For example, a CONFIGSIZE value of LARGE allows a maximum of 512 dbslices. If you set CONFIGSIZE to LARGE and specify a MAX_DBSLICES value of 10, the maximum number of dbslices is 512. For more information, see CONFIGSIZE.

When you allocate the initial chunk for the root dbspace of any coserver, you must ensure that enough space is available for the safewrite area. Allow an extra 6.2 megabytes for a CONFIGSIZE of LARGE, plus 20 bytes per additional dbslice for the safewrite area. Add this amount to the size of the initial chunk of the root dbspace in each coserver. In the formula, additional_dbslices means more dbslices than the CONFIGSIZE maximum (513 to 2047 dbslices).

total space for the safewrite area in bytes=
6200000 bytes + (20 bytes * additional_dbslices) 

If the safewrite area does not have enough space, the database writes a message to the transaction log to report this situation. If insufficient space is available in the root dbspace, you might need to reinitialize the database server and reload your data.