Disabling Disk Error Recovery

Caution: Setting disk drive parameters must be performed correctly on approved disk drive types only. Performing the procedure incorrectly, or performing it on an unapproved type of disk drive could severely damage the disk drive. Setting disk drive parameters should be performed only by experienced system administrators. The procedure for setting disk drive parameters is shown below. In this example all of the parameters shown in Table 9-1 are changed for a disk on controller 131 at drive address 1.

1. Start fx in expert mode:

# fx -x 
fx version 6.2, Oct 10, 1995

1. Specify the disk whose parameters you want to change by answering the prompts:

fx: "device-name" = (dksc) <Enter> 
fx: ctlr# = (0) 131 
fx: drive# = (1) 1 
fx: lun# = (0)
...opening dksc(131,1,0)


...controller test...OK

1. Confirm that the disk drive is one of the approved types listed in Table 9-2 by comparing the next line of output to the table.

Scsi drive type == SGI     0664N1D         6s61
----- please choose one (? for help, .. to quit this menu)-----
[exi]t               [d]ebug/             [l]abel/
[b]adblock/          [exe]rcise/          [r]epartition/

1. Show the current settings of the disk drive parameters (this command uses the shortcut of separating commands on a series of hierarchical menus with slashes):

fx > label/show/parameters

----- current drive parameters-----
Error correction enabled          Enable data transfer on error
Don't report recovered errors     Do delay for error recovery
Don't transfer bad blocks         Error retry attempts          10
Do auto bad block reallocation (read)
Do auto bad block reallocation (write)
Drive readahead  enabled          Drive buffered writes disabled
Drive disable prefetch   65535    Drive minimum prefetch         0
Drive maximum prefetch   65535    Drive prefetch ceiling     65535
Number of cache segments     4
Read buffer ratio        0/256    Write buffer ratio         0/256
Command Tag Queueing disabled


----- please choose one (? for help, .. to quit this menu)-----
[exi]t               [d]ebug/             [l]abel/
[b]adblock/          [exe]rcise/          [r]epartition/

The parameters in Table 9-1 correspond to "Do auto bad block reallocation (read)," "Do auto bad block reallocation (write)," and "Do delay for error recovery," in that order. Each of them is currently enabled.

1. Give the command to start setting disk drive parameters and press <Enter> until you reach a parameter that you want to change:

fx> label/set/parameters
fx/label/set/parameters: Error correction = (enabled) <Enter>
fx/label/set/parameters: Data transfer on error = (enabled) <Enter>
fx/label/set/parameters: Report recovered errors = (disabled) <Enter>

1. To change the delay for error recovery parameter to disabled, enter "disable" the prompt:

fx/label/set/parameters: Delay for error recovery = (enabled) disable

1. Press <Enter> through other parameters that don't need changing:

fx/label/set/parameters: Err retry count = (10) <Enter>
fx/label/set/parameters: Transfer of bad data blocks = (disabled) <Enter>

1. To change the auto bad block reallocation parameters, enter "disable" at their prompts:

fx/label/set/parameters: Auto bad block reallocation (write) = (enabled) disable
fx/label/set/parameters: Auto bad block reallocation (read) = (enabled) disable

1. Press <Enter> through the rest of the parameters:

fx/label/set/parameters: Read ahead caching = (enabled) <Enter>
fx/label/set/parameters: Write buffering = (disabled) <Enter>
fx/label/set/parameters: Drive disable prefetch = (65535) <Enter>
fx/label/set/parameters: Drive minimum prefetch = (0) <Enter>
fx/label/set/parameters: Drive maximum prefetch = (65535) <Enter>
fx/label/set/parameters: Drive prefetch ceiling = (65535) <Enter>
fx/label/set/parameters: Number of cache segments = (4) <Enter>
fx/label/set/parameters: Enable CTQ = (disabled) <Enter>
fx/label/set/parameters: Read buffer ratio = (0/256) <Enter>
fx/label/set/parameters: Write buffer ratio = (0/256) <Enter>

1. Confirm that you want to make the changes to the disk drive parameters by entering "yes" to this question and start exiting fx:

 * * * * * W A R N I N G * * * * *
about to modify drive parameters on disk dksc(131,1,0)! ok? yes

----- please choose one (? for help, .. to quit this menu)-----
[exi]t             [d]ebug/           [l]abel/           [a]uto
[b]adblock/        [exe]rcise/        [r]epartition/     [f]ormat
fx> exit

1. Confirm again that you want to make the changes to the disk drive parameters by pressing <Enter> in response to this question:

label info has changed for disk dksc(131,1,0).  write out changes? (yes) <Enter>