Converting DB2 to Systems Manag ed Storage 79
• Active logs and BSDS.
8.5.2 Methodology
8.5.2.1 Conversion Window
Decide when each type of data is availablefor conversion. During a normal
processing cycle,some data sets will be deleted and reallocated, providing the
opportunity for SMS management. Online data must be converted when those
services are unavailable(down time). This is the most difficult to schedule, and
requires precise planning.
8.5.2.2 Data Movement
Each disk device iseither SM S managedor not.A data set is considered SMS
managed when:
• It has a valid Storage Class.
• It resides on a volume in an SMS Storage Group,or has been migrated by
DFSMShsm.
Data sets can be:
• Converted with movement
• Converted in place
Converted with Movement
This is achievedby using a space management function such as DFSMSdss
COPY,DFSMSdss DUMP/RESTORE or DFSMShsm. This method is applicable if
the data is application owned. However,consideration must be given to the
number of spare disk devicesrequired, while this method is in progress. Also,
consider usingt hisapproach if the disk devices being used are positioned with
storage controlsof varying performance (caching). An advantage with this
method is allowingdata to be allocated using volume thresholds set for each
Storage Group,thus allowing space management to operate.
For tablespaces, the DB2 utility REORG can be used to automatically convert
with data movementif the tablespace is DB2 defined. If it user defined, then a
IDCAMS DELETE/DEFINE CLUSTER must be executedbetween the REORG
phases.
Converted in Place
This is achievedby using DFSMSdss CONVERTV function. This approach
requires exclusiveuse of the data sets residing on the disk device. Ifdata sets
are already positioned in pools of volumes,this may be an appropriate method to
use (tablespacesare likely to be grouped this way). Be warned, if the volume and
data sets do not meet all SMS requirements,DFSMSdss will set the volume's
physicals tatusto initial. This status will allow data sets be accessed, but not
extended.New allocationson the volume are prevented. If all requirements are
met, DFSMSdss will set th e volume status to CONVERTED.
8.5.2.3 Tailor Online Conversion
Many installationshave data sets that are open and active most of the time.
Staging a conversioninto smaller manageable portions of data provides safer
implementation results.