MAX_CHUNKS

onconfig.std
value

0

units

Number of chunks

range of values

0 through 32,767

takes effect

When shared memory is initialized

refer to

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

MAX_CHUNKS allows you to increase the maximum number of chunks up to 32,767. The safewrite area in the first chunk of the root dbspace grows to accommodate the new maximum number of chunks. If you set the MAX_CHUNKS value and later decrease it, the database server ignores the new value and uses the previously set value. However, you can increase the MAX_CHUNKS value at any time.

The database server ignores the MAX_CHUNKS value if it is smaller than the number of chunks that CONFIGSIZE allows. For example, a CONFIGSIZE value of LARGE allows a maximum of 8192 chunks. If you set CONFIGSIZE to LARGE and specify a MAX_CHUNKS value of 2048, the maximum number of chunks is 8192. 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 302 bytes per additional chunk 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_chunks means more chunks than the CONFIGSIZE maximum (8193 to 32,767 chunks).

total space for the safewrite area in bytes = 
6200000 bytes + (302 bytes * additional_chunks) 

If you do not provide enough space for the safewrite area, 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.