This section covers the following topics:
See also Natural Roll Server Functionality.
This section describes the Roll Server system requirements.
Link the module NATRSMvr
(vr represents the relevant product
version) to an
Authorized Program Facility (APF) library, specifying
IEWL parameter AC(1). Refer to
Installing Natural on
z/OS.
As the Roll Server reserves one system linkage index (System LX), check
whether there is a high enough value of NSYSLX in member
IEASYSxx of library
SYS1.PARMLIB.
When the Roll Server terminates, its address space ID is no longer available because a System LX has been used. It becomes available again with the next IPL.
Once a System LX has been reserved, it is reused with every restart of the Roll Server until the next IPL.
| Storage | Size |
|---|---|
| ECSA | 84 bytes |
| Private program storage | 30 KB above |
| Fixed subpool storage (incl. ELSQA): | 10 KB below, 50 KB above |
| LRB directory | 32+(64*number of LRB slots) |
| 100 slots per roll file | 4 KB above |
| Every additional roll file | 30 KB above |
| Working storage | depending on load, about 1 MB above |
A CF structure is used to hold the roll file directory in a z/OS Parallel Sysplex environment.
In a z/OS Parallel Sysplex environment, the Roll Servers communicate via the XCF Signaling Services. As the default XCF group name, the leftmost eight bytes of the CF structure name are used.
If you want to specify your own XCF group name, use the
NATRSU24 user exit. For more information on this user exit, see
NATRSU24 User
Exit.
To format the roll file, proceed as follows:
Allocate it as a physical, sequential data set with a fixed-record format.
Format it using module NATRSRFI.
During formatting, the roll file is converted to BDAM format with a device-dependent block size.
Anmerkung:
If you plan to use an existing roll file of a previous version, it is
sufficient to execute the NATRSRFI RESET function.
To format, enter the following parameter string under the DD name
RFIPARMS, or as PARM on the JCL EXEC
statement:
| function,dd-name,slot-size,number-of-slots |
All parameters are positional; they are explained in the table below:
To calculate the required disk space in cylinders for a roll file
(SPACE parameter of the DD statement), use
the following formula:
number-of-cylinders = ceiling (number-of-slots * slot-size / (30*block-size))
or in tracks
number-of-tracks = ceiling (number-of-slots * slot-size / (2*block-size))
The block size used is:
23476 for 3380 DASD
27998 for 3390 DASD
22928 for 9345 DASD
In addition, space is needed for the roll file directory header (40 bytes) and one directory entry for each roll file slot (24 bytes). Thus, one additional block is needed for roughly 976 slots on 3380, 1164 slots on 3390, or 953 slots on 9345 DASD.
If a DD statement with ddname
RFIPRINT is specified, NATRSRFI directs its output to
this data set. When RFIPRINT is omitted, output is written to
JESMSGLG using the WTO macro
(ROUTDCE=11). Note that RFIPRINT must be specified
for the LIST function.
The following condition codes are used:
| Code | Explanation |
|---|---|
0 |
Normal completion. |
4 |
Number of slots formatted is less than requested. |
20 |
Parameter error. |
The following user abend codes are used:
| Abend Code | Cause |
|---|---|
U0100 |
Open for RFIPARMS or RFIPRINT
failed.
|
U0101 |
Open for roll file failed. |
In the following examples, vr or vrs represents the relevant product version.
Example 1:
//FBRUNRFI JOB (FB,218),FB,CLASS=K,MSGCLASS=X,NOTIFY=FB //FORMAT EXEC PGM=NATRSRFI //STEPLIB DD DISP=SHR,DSN=NATURAL.NATvr.LOAD //RF1 DD DISP=SHR,DSN=FB.SYSF.ROLLF1 //RF2 DD DISP=SHR,DSN=FB.SYSF.ROLLF2 //RFIPARMS DD * FORMAT,RF1,200000,1000 FORMAT,RF2,200000
Excerpt from resulting JESMSGLG:
+FBRUNRFI: FORMAT,RF1,200000,1000 +FBRUNRFI: RF1: FB.SYSF.ROLLF1 +FBRUNRFI: Creation date: 2001/06/13 Volume: ADA002(3390) IEC031I D37-04,IFG0554P,FBRUNRFI,FORMAT,RF1,305B,ADA002,FB.SYSF.ROLLF1 +FBRUNRFI: Not enough space for 1000 slots. +FBRUNRFI: 60 Blocks written. Block size is 27998. +FBRUNRFI: 1 Directory block. +FBRUNRFI: 8 Blocks per slot. Slot size is 223984. +FBRUNRFI: 7 Slots initialized. Roll file version vrs. +FBRUNRFI: 3 Blocks unused. +FBRUNRFI: FORMAT,RF2,200000 +FBRUNRFI: RF2: FB.SYSF.ROLLF2 +FBRUNRFI: Creation date: 2001/06/08 Volume: USRF08(3380) IEC031I D37-04,IFG0554P,FBRUNRFI,FORMAT,RF2,020F,USRF08,FB.SYSF.ROLLF2 +FBRUNRFI: 60 Blocks written. Block size is 23476. +FBRUNRFI: 1 Directory block. +FBRUNRFI: 9 Blocks per slot. Slot size is 211284. +FBRUNRFI: 6 Slots initialized. Roll file version vrs. +FBRUNRFI: 5 Blocks unused.
Example 2:
//FBRUNRFI JOB (FB,218),FB,CLASS=K,MSGCLASS=X,NOTIFY=FB //FORMAT EXEC PGM=NATRSRFI,PARM='FORMAT,RF1,200000' //STEPLIB DD DISP=SHR,DSN=NATURAL.NATvr.LOAD //RF1 DD DISP=SHR,DSN=FB.SYSF.ROLLF1 //RFIPRINT DD SYSOUT=X
Resulting RFIPRINT:
Natural Roll Server - Roll File Utility Version vrs FORMAT,RF1,200000 RF1: FB.SYSF.ROLLF1 Creation date: YYYY/MM/DD Volume: ADA002(3390) 60 Blocks written. Block size is 27998. 1 Directory block. 8 Blocks per slot. Slot size is 223984. 7 Slots initialized. Roll file version vrs. 3 Blocks unused.
You can format or reset several roll files at once by specifying
several parameter lines in RFIPARMS.
You cannot format or reset a roll file while the roll server is active.
When the roll file is formatted in a z/OS Parallel Sysplex
environment, the roll server Coupling Facility structure must also be cleared
using the SETXCF operator command, for example:
SETXCF FORCE,STR,STRNAME=NATROLL1
You start the Roll Server either as a batch job or as a started task by
executing module NATRSMvr (where
vr represents the relevant product
version). The roll
file(s) must be defined as DD statements with ddname
ROLLF1 to ROLLF5.
On the JCL EXEC statement, specify as
PARM the following parameters:
subsystem-id,number-of-roll-files,number-of-LRB-slots,LRB-slot-size,CF-structure-name,low-water-mark,high-water-mark,non-activity-time,timeout-check-time,message-case
All parameters are positional and must be separated by a comma. They are explained in the table below:
| Parameter | Possible Values | Default | Comment |
|---|---|---|---|
subsystem-id
|
4-byte non-blank string | NATv
|
The specified value must match the value of the Natural profile
parameter Anmerkung: |
number-of-roll-files
|
0 - 5 |
1 |
In a z/OS non-Parallel Sysplex environment, the Roll Server can operate without a roll file, using only the in-storage Local Roll Buffer. |
number-of-LRB-slots
|
1 - 32767 |
none |
The number of LRB slots multiplied by the slot size must not exceed 2 GB. The same number of LRB slots is assigned for each LRB, i.e. for each roll file used. The total number of LRB slots is calculated by the formula: number-of-roll-files * number-of-LRB-slots |
LRB-slot-size
|
any numeric value | roll file slot size | Value in number of bytes.
This parameter must be specified if no roll file is used. If roll files are used, this parameter is ignored and the roll file slot size is used instead. |
CF-structure-name
|
any valid structure name | none | If you specify less than 16 characters, blanks are appended.
Only specify this parameter if you use the Coupling Facility (with z/OS Parallel Sysplex). |
low-water-mark
|
0 - 9 |
|
Specifies the low water mark in steps of 10 percent of the number of LRB slots. |
high-water-mark
|
0 - 10 |
|
Analogous to
low-water-mark parameter.
Value "10" means that the staging task will never be activated. It is only recommended to specify "10" if the LRB is large enough to serve all simultaneously active Natural sessions. |
non-activity-time |
1 - 999999
|
none | Number of hours a session can be inactive before it is deleted
from the roll file.
If this time is exceeded, the session is deleted during the next scheduled timeout check. If this parameter is omitted, no timeout check will be executed. This parameter can be changed using operator command
|
timeout-check-time |
0000 - 2359 |
none | The time of day that the timeout check is to be run.
Sessions will be deleted if they have been inactive longer than the non-activity time specified by the preceding parameter. If this parameter is omitted, no timeout check will be scheduled. This parameter can be changed using operator command
|
message-case |
UCTRAN or blank
|
blank | Specify UCTRAN if the Roll Server is to issue all
its messages in upper case.
|
Anmerkung:
The Local Roll Buffer resides in a Memory Object "above the
bar". Use the MEMLIMIT parameter on the
EXEC statement to ensure enough memory can be allocated
"above the bar".
In the following examples, vr represents the relevant product version
// EXEC PGM=NATRSMvr,PARM='NAvr,,1000' //ROLLF1 DD DSN=SYSF.ROLLFILE
The subsystem ID is NAvr, one
roll file is used (default), and the Local Roll Buffer has 1000 slots. The slot
size used is identical with the roll file's slot size. The low water mark is 70
percent (default), the high water mark is 80 percent (default).
// EXEC PGM=NATRSMvr,PARM=',5,1000,150000,NATROLL1',MEMLIMIT=800M //ROLLF1 DD DSN=DASD1.ROLLFILE //ROLLF2 DD DSN=DASD2.ROLLFILE //ROLLF3 DD DSN=DASD3.ROLLFILE //ROLLF4 DD DSN=DASD4.ROLLFILE //ROLLF5 DD DSN=DASD5.ROLLFILE
The subsystem ID is NATv
(default), five roll files are used, and each of the five Local Roll Buffers
has 1000 slots. The LRB slot size is 150000 bytes. The roll file directory
resides in the Coupling Facility structure NATROLL1. Low and high
water marks are ignored, because every thread is written to the roll file (see
Natural Roll Server
Functionality). Since this job is intended for z/OS, the
MEMLIMIT option specifies 800 Megabytes for the Local Roll
Buffers.
Anmerkung:
The Roll Server will not start in the following cases:
Another Roll Server is running with the same subsystem-id.
Another Roll Server is accessing a roll file specified in its JCL
A roll file has been reformatted without resetting the CF structure,
using the SETXCF FORCE command.
The Roll Server writes informational and error messages to
JESMSGLG using the WTO macro
(ROUTCDE=11). The messages are preceded by a message identifier
and the Roll Server's job name, for example:
RSM0019 FBRSMvrs: Roll Server Version vrs is active
where vrs represents the relevant product version.
The messages are explained in the section Roll Server Messages in the Messages and Codes documentation.
The following condition codes are used:
0
|
Normal completion |
12
|
Wrong parameter input |
16
|
Runtime error |
20
|
Abend has occurred |
>100
|
Initialization error |
When an unexpected return code is issued by an XCF or XES Service Call, an abend with a dump is forced. Register 14 of the abend register contains the reason code. To find a description of the reason, refer to Programming: Sysplex Services Reference (IBM documentation). If the error was not environment-specific, send the dump to Software AG support.
The following user abend codes are used:
| Abend Code | Cause |
|---|---|
U0200
|
IXLCONN failed
|
U0201
|
IXLFORCE failed
|
U0202
|
IXLLIST failed
|
U0203
|
IXLDISC failed
|
U0204
|
IXCLEAVE failed
|
U0301
|
IXLLIST failed
|
U0302
|
IXCMSGO failed
|
U0401
|
IXLLIST failed
|
U0501
|
IXLLIST failed
|
These are codes that Natural may receive from the Roll Server's PC services routines. They are reported by the respective teleprocessing interfaces (Natural CICS Interface or Natural IMS TM Interface). For a list of these codes, refer to the Return Codes and Reason Codes of the Roll Server Request in the Messages and Codes documentation.
The following commands can be passed to the Roll Server via the
MODIFY operator command:
As a general rule for Roll Server performance tuning, give the Roll Server a higher dispatching priority than the address spaces where Natural runs.
To find out where the weaknesses in performance are, analyze the system
performance using the
Natural
Subsystems and Roll Server Information function of the
SYSTP utility.
When looking at Roll-Server Statistics, keep an eye especially on the following values:
The number of direct writes.
"Direct write" means that the Natural thread that was received was written to the roll file directly.
There are two possible reasons:
No LRB slot available. Increase the LRB.
The compressed thread was larger than a single LRB slot. Increase the LRB slot size.
The number of direct reads.
"Direct read" means that the requested thread was no longer in the LRB and had to be read directly from the roll file.
If the ratio of direct reads to the total number of reads is very high in a single z/OS system, the LRB is too small (increase it).
If the ratio of direct reads to the total number of reads is very high in a z/OS Parallel Sysplex environment, this may also mean that there are many inter-system activities, which in turn means that a Natural session changes z/OS images quite frequently during its lifetime.
The number of staging waits (in a single z/OS environment).
A "staging wait" is a situation where a write request had to wait until the Staging Task had written the LRB slot to the roll file. If the ratio of staging waits to the total number of write requests is very high, this indicates that the high and low water marks are set inappropriately or that there is a bottleneck on the roll file device/roll file channel.
Based on experience with stress tests, the following is recommended:
If the ratio of maximal number of active users to number of LRB slots is very small, increase the high water mark. If not, decrease the high water mark.
The difference between high water mark and low water mark should not be larger than three (30 percent).
Ideally, if the number of LRB slots is definitely larger than the maximum number of concurrent users, the high water mark should be set to 10.
The roll server has two user exits.
Sample source modules are delivered for these.
Specifies the roll file number to be used.
Entry calling conventions:
Register 1 addresses the parameter list that is described by the
following DSECT:
PLIST DSECT PLRSVER DS CL4 Roll server version (= 'vrs') PLNRF DS H Number of roll files PLUID DS CL16 Userid PLTSNUM1 DS H Total number of slots Roll file 1 PLUSNUM1 DS H Number of slots in use Roll file 1 PLTSNUM2 DS H Total number of slots Roll file 2 PLUSNUM2 DS H Number of slots in use Roll file 2 PLTSNUM3 DS H Total number of slots Roll file 3 PLUSNUM3 DS H Number of slots in use Roll file 3 PLTSNUM4 DS H Total number of slots Roll file 4 PLUSNUM4 DS H Number of slots in use Roll file 4 PLTSNUM5 DS H Total number of slots Roll file 5 PLUSNUM5 DS H Number of slots in use Roll file 5 PLISTL EQU *-PLIST
where vrs represents the relevant product version.
Register 13 points to a 36-fullword save area.
Register 14 contains the return address.
Register 15 contains the entry address of NATRSU14.
Return calling convention:
Register 15 contains the number of the roll file in binary format.
Anmerkung:
If access registers are modified within this user exit, these
access registers must be saved and restored on return. This user exit is called
in primary addressing mode with PSW Key 8. Since it runs in
cross-memory mode, no SVC except SVC 13 may be used.
Specifies the XCF group name to be used.
Entry calling conventions:
Register 1 points to an 8-byte area in which the group name must be generated.
Register 13 points to an 18-fullword save area.
Register 14 contains the return address.
Register 15 contains the entry address of NATRSU24.
As a group name default, the Roll Server will use the leftmost 8 bytes of the CF structure name.
This user exit is called in primary mode, PSW Key 8 and in task mode.