OAM provides multiple options for adding objects to the object
storage hierarchy to address varied application virtual storage environments:
- STORE function
- The STORE function can be used with 31-bit addressable virtual
storage buffers or 64-bit addressable virtual storage buffers. When
using 31-bit addressable virtual storage buffers, the STORE function
can be used for objects whose size is less than or equal to 256 megabytes
(268,435,456 bytes) that are to be written to the disk, tape, or optical
levels of the storage hierarchy. When using 64-bit addressable virtual
storage buffers, the STORE function can be used for objects from 1
byte to 2000 megabytes (2,097,152,000 bytes) that are to be written
to the disk or tape levels of the storage hierarchy and for objects
from 1 byte to 256 megabytes (268,435,456 bytes) that are to be written
to the optical level of the storage hierarchy. STORE processing requires
that the entire object exist in virtual storage. See STORE function for more information.
- Store Sequence functions
- Store Sequence can be used for objects whose size is greater than
50 megabytes (52,428,800 bytes) that are to be written to the disk
or tape (but not optical) levels of the storage hierarchy. Store Sequence
processing handles objects in smaller parts, rather than having the
entire object in storage (as required by STORE processing), which
can reduce the virtual storage requirements for an application. See STOREBEG—Beginning a Store Sequence operation, STOREPRT—Storing an individual part in a Store Sequence operation, and STOREEND—Ending a Store Sequence operation for more information.
When storing objects in the DB2 sublevel, the LOB configuration
must support the following cases when object data is always written
to a LOB table:
- STORE with 64-bit addressable virtual storage buffers for objects
greater than 256 megabytes (268,435,456 bytes) are always written
to a LOB table
- Store Sequence processing always writes the objects to a LOB table.
Therefore, if LOB=N is specified on the OAM1 entry in the IEFSSNxx
parmlib member, or if a LOB storage structure does not exist for the
target object storage group in these cases, then the attempt to do
the STORE or Store Sequence to the DB2 sublevel will fail.
Table 1 can be
used to help decide which OAM store function is appropriate for the
application virtual storage environment.
Table 1. Deciding which OAM store function to use| OSREQ
Function |
Virtual
Storage Buffers |
Minimum
Object Size |
Maximum
Object Size |
OAM
Storage Hierarchy Location |
When to Use |
|---|
| DSL1 (DB2) |
DSL2 (File System) |
Tape |
Optical |
|---|
| STORE with BUFLIST and SIZE |
31-bit |
1 byte |
256M |
Yes |
Yes |
Yes |
Yes |
Storing objects less than or equal to 256M in
size and all object data can be made available in virtual storage
at one time. |
|---|
| STORE with BUFFER64 and SIZE64 |
64-bit |
1 byte |
2000M1 |
Yes |
Yes |
Yes |
Yes1 |
Storing objects greater than 256M, exploiting
64-bit virtual storage, and all object data is available in 64-bit
virtual storage. Can also be used for objects less than or equal to
256M, but STORE with BUFLIST and SIZE is recommended for efficiency. |
|---|
| STOREBEG, STOREPRT, and STOREEND |
31-bit |
Greater than 50M |
2000M |
Yes |
Yes |
Yes |
No |
Storing objects greater than 50M, but not exploiting
64-bit virtual storage and all object data can not be made available
in virtual storage at one time. |
|---|
Note: Although 2000M is the maximum size supported by OAM, the actual
maximum is installation dependent and might be less than 2000M.
