Dynamic Load Balancer Plustm
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14.5.4 Authorization Parameter Changes

Both RMS local buffering and global buffering require increased address space and additional OpenVMS synchronization information. The following MINIMUM authorization parameter values are recommended when either local buffering or global buffering is specified:
  SYSUAF
Parameter Name 		Minimum
Value
  PGFLQUO 35000
  BYTLM 50000

14.5.5 SYSGEN Parameter Changes

RMS global buffering requires increased use of OpenVMS global pages and global sections. In addition, some RMS related SYSGEN parameters must be changed. The following MINIMUM SYSGEN parameter values are recommended when global buffering is specified:
  SYSGEN
Parameter name 		Minimum
Value
  GBLPAGFIL 16384
  GBLPAGES 50000
  GBLSECTIONS 800
  RMS_GBLBUFQUO 16384

Both RMS local buffering and global buffering require increased use of OpenVMS locking and synchronization resources. The following MINIMUM SYSGEN parameter values are recommended when either local buffering or global buffering is specified:
  SYSGEN
Parameter name 		Minimum
Value
  IRPCOUNT 500
  LOCKIDTBL 4000
  LOCKIDTBL_MAX 16000
  PQL_MENQLM 600
  RESHASHTBL 2500
  SRPCOUNT 4500
  VIRTUALPAGECNT 35000

Note
The IRPCOUNT and SRPCOUNT SYSGEN parameters only exist in version 5.x of OpenVMS. These parameters are not used by OpenVMS 6.x.

After making changes to SYSGEN parameters, the system must be rebooted for the changes to take effect.

14.6 Disk Defragmentation

Disk defragmentation is the process that causes files to become physically contiguous. Contiguous files can be accessed with fewer I/O operations than non-contiguous files. The two ways to defragment a disk are to do a full BACKUP and RESTORE to the target disk or to use a commercially available disk defragmentation product.

14.7 File Defragmentation

If you don't have the time to defragment all of your disks, you can instead defragment your most badly fragmented files one at a time.

OpenVMS provides a way to defragment individual files. There are three steps to the defragmentation process:

14.7.1 Create an .FDL for the File

An .FDL is a "file definition language" file. This file can be used with the Digital provided OpenVMS CONVERT utility to defragment a file. To create a .FDL for the file SALESM.DAT you would use the following DCL command: 


    $ ANALYZE/RMS/FDL SALESM.DAT

The ANALYZE command creates a file called SALESM.FDL. The .FDL is a text file containing a description of SALESM.DAT.

14.7.2 Customize the .FDL File

Using the text editor of your choice, edit the .FDL file and insert the text "best_try_contiguous yes" as shown: 



------------------------------------------------------------------ 
  FILE 
          best_try_contiguous     yes      <--- the inserted text 
          ALLOCATION              nnn 
          ORGANIZATION            xxx 
            . 
            . 
            . 
------------------------------------------------------------------

14.7.3 Converting and Renaming

The Digital provided CONVERT utility can be used to defragment and reorganize your files using a .FDL. To convert and defragment the file SALESM.DAT, at the DCL prompt enter: 


    $ CONVERT/FDL=salesm.fdl salesm.dat  salesm.new 
 
    $ RENAME  salesm.new  salesm.dat;  (note the trailing ";")

Note
If the CONVERT fails, DO NOT DO THE RENAME. THIS INSURES THE INTEGRITY OF YOUR ORIGINAL UNCONVERTED FILE.

Chapter 15
DLB Plus Performance Options

15.1 Tuning Versus Biasing

DLB Plus is designed to balance resources on your VAX. Each process receives a balanced and fair share of system resources. No one process is able to "take over the system" and slow everyone else down. DLB Plus balances resources by constantly tuning the system, adjusting it for optimum performance.

Biasing is a method that improves response times for certain types of processes at the expense of other processes. DLB Plus can perform biasing by dynamically changing CPU time allocation and process priority levels. DLB Plus also changes related SYSGEN parameters.

Note
By default DLB Plus does not bias processes. It does so only if run with the optional biasing options.

15.2 Requesting DLB Plus Operation Options

DLB Plus has six different operation options. Any one of these options can be selected at any time. The options are:

DLB Plus operation options can be specified either at startup or at any time the software is operating.

To request any DLB Plus option or combination of options at DLB Plus startup time, use the following with your DLB Plus startup command: 


    $ @SYS$SYSDEVICE:[TTI_DLBPLUS]DLBPLUS_STARTUP "option1, option2, ..."

For example: 


    $ @SYS$SYSDEVICE:[TTI_DLBPLUS]DLBPLUS_STARTUP "BIAS IO, ONLY CPU"

If you are starting up fragmentation prevention when you start up DLB Plus, option1 will be CD. For example: 


    $ @SYS$SYSDEVICE:[TTI_DLBPLUS]DLBPLUS_STARTUP "CD, BIAS IO, ONLY CPU"

To request any DLB Plus option or combination of options while DLB Plus is operating, use the following DCL command: 


    $ DEFINE/SYSTEM/NOLOG DLB_PROCESS_CMD "option1, option2, ..."

where "option1, option2, ..." are DLB Plus software options.

For example: 


    $ DEFINE/SYSTEM/NOLOG DLB_PROCESS_CMD "BIAS IO, ONLY CPU"

Caution
The DLB Plus software options MUST be typed in UPPERCASE (i.e. BIAS IO, ONLY CPU).

To display the current DLB Plus bias option settings, use the DLB Plus DISPLAY utility. This is menu item DISPLAY on the Master Menu.

The following table lists the effects of DLB Plus bias options on the operation of DLB Plus.

Table 15-1 Bias Options Adjustments
Bias Option Priorities Memory CPU Scheduling
BIAS NONE no yes yes
BIAS CPU no yes yes
BIAS IO yes yes yes
BIAS INTERACTIVE yes yes yes
ONLY CPU no no yes
ONLY MEMORY no yes no

The following section details each of the bias options.

15.2.1 Bias Options

BIAS NONE

Gives no process type more CPU access or time than another. This is the default setting for DLB Plus. Choosing this option turns off any biasing.

BIAS CPU

Gives CPU bound processes a larger portion of CPU time. This improves the throughput of CPU bound processes.

BIAS IO

Gives all I/O bound processes increased access to the CPU. This improves the response times of disk I/O bound and interactive processes.

BIAS INTERACTIVE

Boosts current priority of interactive processes. These are processes that spend a lot of time waiting for terminal I/O.

ONLY CPU

Stops memory adjustment, causing DLB Plus software to perform only CPU adjustment.

ONLY MEMORY

Adjusts only memory resources. No scheduling resources are adjusted.

Chapter 16
Using DLB Plus with Host-Based Data Caching Systems

DLB Plus is the perfect companion for host-based data caching systems. Caching systems use host memory to cache disk I/O requests. The more memory you have available to the caching system, the better job the caching system does in reducing I/O bottlenecks.

16.1 Using DLB Plus with I/O EXPRESStm

I/O EXPRESS (IOX) is greatly enhanced when used in conjunction with DLB Plus. However, in order for IOX to fully take advantage of the additional memory released by DLB Plus, some IOX parameter settings must be adjusted.

When using I/O EXPRESS with DLB Plus, we recommend the following parameter settings:

Table 16-1 I/O EXPRESS Initialization Parameters
Parameter DLB Plus Suggested Value Description
/TIMER_INTERVAL 3 Time interval in seconds between IOX house-keeping cycles. It is during this time that IOX returns cache memory to the free list.
/MAX_RETURN 128 * VUPS Maximum number of cache memory pages to return to the free list each house-keeping cycle.
/MEMORY_CRISIS 10 percent of memory When the free list falls to this level, cache memory is returned to the free list.
/ALLOCATION_LIMIT MEMORY_CRISIS + MAX_RETURN When the free list falls to this level, no new memory is allocated to the cache.
/TRIM_GOAL ALLOCATION_LIMIT + MAX_RETURN During a memory crisis, when the free list rises to this level, IOX stops returning cache to the free list.

Note
The I/O EXPRESS adjustments for use with DLB Plus given here are recommendations made by Rick Cadruvi, developer of I/O EXPRESS and co-developer of DLB Plus. If you have any questions about these settings, please call Touch Technologies, Inc. Technical Support.

16.1.1 Adjusting I/O EXPRESS for use with DLB Plus

Although I/O EXPRESS parameter changes can be made by hand, the DLB Plus directory contains the command procedure DLB_IOX_INIT.COM. This command procedure calculates the amount of memory used on your system and the VUP rating of your system. For SMP systems, this is the VUP rating of each CPU.

The command procedure then uses the memory and VUP values to calculate optimal IOX parameter settings. Next, it executes the I/O EXPRESS IOX_INIT.EXE program and makes the changes to I/O EXPRESS.

Note
The DLB_IOX_INIT.COM procedure must be executed AFTER both IOX and DLB Plus have been started up on your system.

If you are on a VAX Cluster, the DLB_IOX_INIT.COM procedure must be executed on all nodes in the cluster that are running both DLB Plus and I/O EXPRESS.

Example 16-1 Typical SYSTARTUP_V5.COM Fragment Starting Up Both IOX and DLB Plus 

   . 
   . 
$! Note:  Execute the command procedures in the order below. 
$ 
$ @SYS$SYSDEVICE:[IOEXPRESS]IOX_STARTUP 
$ @SYS$SYSDEVICE:[TTI_DLBPLUS]DLBPLUS_STARTUP 
$ @TTI_DLB:DLB_IOX_INIT 
   . 
   .

Note

tm I/O EXPRESS is a trademark of Executive Software International.

1 Rick Cadruvi is the President of Software Perspectives, developers of I/O EXPRESS. I/O EXPRESS is marketed by Executive Software International.

16.2 Using DLB Plus with SuperCache tm

SuperCache (SCACHE) is greatly enhanced when used in conjunction with DLB Plus. However, to ensure maximum performance between SuperCache and DLB Plus, we suggest that some SuperCache parameter settings be adjusted.

When using SuperCache with DLB Plus, we recommend the following parameter settings:

Table 16-2 SuperCache Initialization Parameters
Parameter DLB Plus Suggested Value Description
/MEMBUFF 10 percent of memory "Guard Zone" which determines the minimum free list size (in pages) before SuperCache begins returning memory from its cache. Set to 1000 pages by default.
/RETURN 20 * VUPS The amount of memory blocks SuperCache is going to release at any one time. Set to 1 by default.

Note
The SuperCache parameter adjustments listed above for use with DLB Plus are recommendations made by Eric Dickman, developer of SuperCache. If you have any questions or concerns regarding these settings, please contact Technical Support at Touch Technologies, Inc.

16.2.1 Adjusting SuperCache for use with DLB Plus

Although SuperCache parameter changes can be made by hand, the DLB Plus directory contains the command procedure DLB_SCACHE_INIT.COM. This command procedure calculates the amount of memory used on your system and the VUP rating of your system. For SMP systems, this is be the VUP rating of each CPU.

The command procedure then uses the memory and VUP values to calculate optimal SCACHE parameter settings. Next, it enables SuperCache caching with the CACHE START DCL command. The modified cache settings are now in effect.

Note
The DLB_SCACHE_INIT.COM procedure must be executed AFTER both SuperCache and DLB Plus have been started up on your system.

If you are on a VAX Cluster, the DLB_SCACHE_INIT.COM procedure must be executed on all nodes in the cluster that are running both DLB Plus and SuperCache.

Example 16-2 Typical SYSTARTUP_V5.COM Fragment Starting Up Both SCACHE and DLB Plus 

   . 
   . 
$! Note:  Execute the command procedures in the order below. 
$ 
$ @SYS$SYSDEVICE:[SCACHE$DIR]START_CACHE 
$ @SYS$SYSDEVICE:[TTI_DLBPLUS]DLBPLUS_STARTUP 
$ @TTI_DLB:DLB_SCACHE_INIT 
   . 
   .

Note

tm SuperCache is a trademark of EEC Systems, Inc.

2 Eric Dickman is one of the developers of SuperCache. SuperCache is distributed in the US and Canada by EEC Systems, Inc.

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