DSNTIP1: Buffer pool sizes panel 1

The DSNTIP1 panel is the first of two panels on which you can specify the size of your virtual buffer pools.

Updating the default buffer pool assignments

You can also change the default buffer pool assignments for user data on this panel. Objects in the catalog and directory always use the following buffer pools, and the assignments cannot be changed: BP0, BP8K0, BP16K0, and BP32K.

It is best to separate the buffer pools for Db2 catalog and directory from the buffer pools for user data to isolate catalog and directory activities. In most cases, choose buffer pools other than the default buffer pools for user data, user indexes, and work files.

For more information about default buffer pool assignments, see Deciding how many buffer pools to use.

Updating the buffer pool sizes

You can change your buffer pool sizes online with the ALTER BUFFERPOOL command, but you cannot change these sizes by running the DSNTINST CLIST in update mode.

Restriction: The total amount of storage that is available in all buffer pools cannot exceed 16 TB. The amount of storage that is configured on the subsystem can further limit the buffer pool sizes. If you specify more storage than the total real storage that is available, performance can be impacted.
Figure 1. Buffer pool sizes panel 1: DSNTIP1
DSNTIP1          INSTALL DB2 - BUFFER POOL SIZES - PANEL 1                
===>                                                                      
                                                                           
Enter 4 KB buffer pool sizes in number of pages.                          
    1 BP0  ==> 20000        18 BP17 ==> 0            35 BP34 ==> 0         
    2 BP1  ==> 0            19 BP18 ==> 0            36 BP35 ==> 0         
    3 BP2  ==> 0            20 BP19 ==> 0            37 BP36 ==> 0         
    4 BP3  ==> 0            21 BP20 ==> 0            38 BP37 ==> 0         
    5 BP4  ==> 0            22 BP21 ==> 0            39 BP38 ==> 0         
    6 BP5  ==> 0            23 BP22 ==> 0            40 BP39 ==> 0         
    7 BP6  ==> 0            24 BP23 ==> 0            41 BP40 ==> 0         
    8 BP7  ==> 0            25 BP24 ==> 0            42 BP41 ==> 0         
    9 BP8  ==> 0            26 BP25 ==> 0            43 BP42 ==> 0         
   10 BP9  ==> 0            27 BP26 ==> 0            44 BP43 ==> 0         
   11 BP10 ==> 0            28 BP27 ==> 0            45 BP44 ==> 0         
   12 BP11 ==> 0            29 BP28 ==> 0            46 BP45 ==> 0         
   13 BP12 ==> 0            30 BP29 ==> 0            47 BP46 ==> 0         
   14 BP13 ==> 0            31 BP30 ==> 0            48 BP47 ==> 0         
   15 BP14 ==> 0            32 BP31 ==> 0            49 BP48 ==> 0         
   16 BP15 ==> 0            33 BP32 ==> 0            50 BP49 ==> 0         
   17 BP16 ==> 0            34 BP33 ==> 0                                  
                                                                           
PRESS:  ENTER to continue   RETURN to exit   HELP for more information

Buffer pool sizes fields BP0 - BP49

The values of fields BP0 - BP49 specify the number of 4 KB buffers in each of those virtual buffer pools (BP0 - BP49).

Acceptable values:
  • BP0: 2000 - 250000000
  • BP1 - BP49: 0 - 250000000
Default:
  • BP0: 20000
  • BP1 - BP49: 0
Update: ALTER BUFFERPOOL command
DSNZPxxx: none