Setting Process Quotas for Efficient Backups

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HP OpenVMS System Manager's Manual, Volume 1:...

Using BACKUP

Understanding BACKUP File Formats

Using Disks and Tapes

Setting Process Quotas for Efficient Backups

You can optimize the efficiency of backups on your system by properly setting the process quotas for the process from which backups will be made (the process from which you enter the BACKUP command or submit your backup command procedure). This is especially important if you are using a streaming tape drive.

How to Perform This Task

To set process quotas for efficient backups, perform the following actions:

Determine which account you want to use for backups. You can use an existing account, or create one solely for backups. For information about creating accounts, see Adding User Accounts.

Use the Authorize utility (AUTHORIZE) to determine the current quota values for the account you will use for backups. For example, if you are using the SYSTEM account for backups, enter the following commands:
```
$ SET DEFAULT SYS$SYSTEM
$ RUN AUTHORIZE
UAF> SHOW SYSTEM
```

Using the System Management utility (SYSMAN), determine the value of the system parameters WSMAX and CHANNELCNT, as follows:

$ RUN SYS$SYSTEM:SYSMAN
SYSMAN> PARAMETERS SHOW WSMAX
%SYSMAN-I-USEACTNOD, a USE ACTIVE has been defaulted on node DIEM
Node DIEM:   Parameters in use: ACTIVE
Parameter Name          Current   Default   Minimum   Maximum Unit  Dynamic
--------------          -------   -------   -------   ------- ----  -------
WSMAX                      2600      1024        60    100000 Pages       
SYSMAN> PARAMETERS SHOW CHANNELCNT

Parameter Name          Current   Default   Minimum   Maximum Unit  Dynamic
--------------          -------   -------   -------   ------- ----  -------
CHANNELCNT                 127       127        21     2047 Channels     
 
SYSMAN> EXIT
$

In this case, the values for WSMAX and CHANNELCNT, as shown in the column marked Current, are 2600 and 127, respectively. Use these values to help set the correct values for the process quotas.

Use AUTHORIZE to compare the values for the process quotas to the recommended values for efficient backups, as shown in Recommended Process Quotas for Efficient Backups.

Table 4 Recommended Process Quotas for Efficient Backups
Process Quota Recommended Setting

WSQUOTA
Equal to system parameter WSMAX

WSEXTENT
Equal to WSQUOTA quota

PGFLQUOTA
Equal to or greater than WSEXTENT quota

FILLM
Less than system parameter CHANNELCNT

DIOLM
Either 4096 or three times the value of FILLM quota, whichever is greater

ASTLM
Either 4096, at least 100 greater than DIOLM quota, or three times the value of FILLM quota, whichever is greater

BIOLM
Equal to FILLM

BYTLM
Equal to or greater than the following value: (256 * FILLM) + (6 * DIOLM)

ENQLM
Greater than FILLM quota

**Table 4** **Recommended Process Quotas for Efficient Backups**
Process Quota	Recommended Setting
WSQUOTA	Equal to system parameter WSMAX
WSEXTENT	Equal to WSQUOTA quota
PGFLQUOTA	Equal to or greater than WSEXTENT quota
FILLM	Less than system parameter CHANNELCNT
DIOLM	Either 4096 or three times the value of FILLM quota, whichever is greater
ASTLM	Either 4096, at least 100 greater than DIOLM quota, or three times the value of FILLM quota, whichever is greater
BIOLM	Equal to FILLM
BYTLM	Equal to or greater than the following value: (256 * FILLM) + (6 * DIOLM)
ENQLM	Greater than FILLM quota

If necessary, change process quotas using the AUTHORIZE command MODIFY. If you change process quotas, you must log out and log in again for the changes to take effect. For information about changing these process quotas, see Modifying a User Account.

Sample Process Quotas for Efficient Backups lists a set of process quota values that are appropriate for many configurations. If your disks are highly fragmented or if your backups will be performed during periods of heavy system use, you should reduce the values shown for WSQUOTA and FILLM.

Table 5 Sample Process Quotas for Efficient Backups
Process Quota Suggested Value

WSQUOTA
16384

WSEXTENT
Greater than or equal to WSQUOTA

PGFLQUOTA
32768

FILLM
128

DIOLM
4096

ASTLM
4096

BIOLM
128

BYTLM
65536

ENQLM
256

**Table 5** **Sample Process Quotas for Efficient Backups**
Process Quota	Suggested Value
WSQUOTA	16384
WSEXTENT	Greater than or equal to WSQUOTA
PGFLQUOTA	32768
FILLM	128
DIOLM	4096
ASTLM	4096
BIOLM	128
BYTLM	65536
ENQLM	256

Example

The following steps show the commands that you would use to run the Authorize utility and set process quotas for the SYSTEM account (if you plan to run backups from a different account, determine the process quotas for that account):

Determine the current quota values:

$ SET DEFAULT SYS$SYSTEM
$ RUN AUTHORIZE
UAF> SHOW SYSTEM

Username: SYSTEM                           Owner:  SYSTEM MANAGER
Account:  SYSTEM                           UIC:    [1,4] ([SYSTEM])
CLI:      DCL                              Tables: DCLTABLES
Default:  SYS$SYSROOT:[SYSMGR]
                                 .
                                 .
                                 .
Maxjobs:         0  Fillm:        40  Bytlm:        32768
Maxacctjobs:     0  Shrfillm:      0  Pbytlm:           0
Maxdetach:       0  BIOlm:        18  JTquota:       1024
Prclm:          10  DIOlm:        18  WSdef:          256
Prio:            4  ASTlm:        24  WSquo:          512
Queprio:         0  TQElm:        20  WSextent:      2048
CPU:        (none)  Enqlm:       200  Pgflquo:      20480
                                 .
                                 .
                                 .
UAF> EXIT

%UAF-I-NOMODS, no modifications made to system authorization file
%UAF-I-NAFNOMODS, no modifications made to network authorization file
%UAF-I-RDBNOMODS, no modifications made to rights database 
$

In this example, SYSTEM has the following quotas:

WSQUOTA
512

WSEXTENT
2048

PGFLQUOTA
20480

FILLM
40

DIOLM
18

ASTLM
24

BIOLM
18

BYTLM
32768

ENQLM
200

Using the System Management utility (SYSMAN), determine the value of the system parameters WSMAX and CHANNELCNT, as follows:

$ RUN SYS$SYSTEM:SYSMAN
SYSMAN> PARAMETERS SHOW WSMAX
%SYSMAN-I-USEACTNOD, a USE ACTIVE has been defaulted on node DIEM
Node DIEM:   Parameters in use: ACTIVE
Parameter Name          Current   Default   Minimum   Maximum Unit  Dynamic
--------------          -------   -------   -------   ------- ----  -------
WSMAX                      2600      1024        60    100000 Pages       
SYSMAN> PARAMETERS SHOW CHANNELCNT

Parameter Name          Current   Default   Minimum   Maximum Unit  Dynamic
--------------          -------   -------   -------   ------- ----  -------
CHANNELCNT                 127       127        21     2047 Channels     
 
SYSMAN> EXIT
$

In this case, the values for WSMAX and CHANNELCNT, as shown in the column marked Current, are 2600 and 127, respectively.

Compare the values for SYSTEM to the values in Recommended Process Quotas for Efficient Backups, and set the appropriate values:

$ SET DEFAULT SYS$SYSTEM
$ RUN AUTHORIZE
UAF> MODIFY SYSTEM/WSQUOTA=2600
UAF> MODIFY SYSTEM/WSEXTENT=2600
UAF> MODIFY SYSTEM/DIOLM=4096
UAF> MODIFY SYSTEM/ASTLM=4096
UAF> MODIFY SYSTEM/BIOLM=40
UAF> MODIFY SYSTEM/BYTLM=34816
UAF> EXIT

Log out and then log in again so that these process quotas take effect.

Understanding BACKUP File Formats

Using Disks and Tapes

WSQUOTA	512
WSEXTENT	2048
PGFLQUOTA	20480
FILLM	40
DIOLM	18
ASTLM	24
BIOLM	18
BYTLM	32768
ENQLM	200