Tivoli Header

Tivoli Space Manager for UNIX Using the Hierarchical Storage Management Clients

dsmmode

Valid for AIX JFS environments only

The dsmmode command sets one or more of the following execution modes to modify the HSM-related behavior of specific commands:

The dsmmode command also displays the current execution modes that are in effect. If you precede another command and its arguments with the dsmmode command, only the execution mode or modes that you specify remain in effect for that command and any child processes of that command. Specify valid options with the dsmmode command for any command that follows to run. If you do not specify options, any command and its associated arguments that follow are ignored.

If you enter the dsmmode command without another command, it starts a new shell and the execution mode or modes that you specify remain in effect until you exit the shell. The shell that starts is the one that you specified as your default shell in /etc/passwd. You can nest dsmmode commands within the new shell.

Syntax

>>-dsmmode--+--------------+--+----------------------------+---><
            | .----------. |  '- command and its arguments-'
            | V          | |
            '--- options-+-'
 
 

Parameters

options
Use any combination of the following options. If you do not specify any options, the current execution modes in effect display.

-Dataaccess=value or -dvalue
Determines how a migrated file appears to the next command that you entered. The values that you can specify are:
Value Description
Normal or n A migrated file appears to be resident, and the command can access the file. This is the default.
Zero-length or z A migrated file appears to be a zero-length file.
Error or e Any attempt to access a migrated file returns an EIO error.

-Timestamp=value or -tvalue
Determines whether the access time (atime) for a file is set to the current time when you access the file. Only a root user can change this mode. The values that you can specify are:
Mode Description
Normal or n The access time is set to the current time when a file is accessed. This is the default.
Preserve or p The access time and inode change time (ctime) do not change when the file is read or its attributes are changed. You can specify this value to prevent access times from changing when backup programs other than the TSM backup-archive client program back up your files.
Note:
If you enter a command, such as the shell command cat, the file you are accessing is then mapped into memory. When a file is mapped, the access time will change even if you specify the preserve option.

-Outofspace=value or -ovalue
Determines how the HSM client responds to out-of-space errors that the kernel returns. The values that you can specify are:
Value Description
Normal or n The HSM client performs demand migration to avoid returning errors to the user if possible, and attempting to recover from out-of-space conditions. This is the default.
Error or e The HSM client does not intercept out-of-space errors.

-Recall=value or -rvalue
Determines how the HSM client recalls a migrated file when it is accessed. You can set a recall mode for a process to normal or migrate-on-close. The following list defines the order of precedence for recall modes if the recall mode that you set for a process is different from the recall mode that you set for a migrated file accessing the process:
  1. Migrate-on-close
  2. Normal

The values that you can specify are:

Value Description
Normal or n When a migrated file is accessed, it is copied to its originating file system. If the file is not modified, it becomes a premigrated file. If the file is modified, it becomes a resident file. Normal is the default recall mode for a process.
Migonclose or m When a migrated file is accessed, the HSM client temporarily copies it to your local file system. If the file is not modified, the file is returned to a migrated state by replacing the file with a stub file on your local file system when it is closed. If the file is modified, it remains on your local file system as a resident file.

Use the dsmattr command to set a recall mode for a migrated file to normal, migrate-on-close, or read-without-recall. See Table 13 for the recall modes that are used.

Attention: More than one process can access a file at a time. Another process can cause a file that you are accessing in migrate-on-close or read-without-recall mode to remain on your local file system as a resident or premigrated file. For example, if the recall mode that you set for a file is normal, and you access it with a process using the migrate-on-close recall mode and you do not modify the file, you would expect the file to be in a migrated state when you close it. But if someone else accesses the file at the same time with a process using normal recall mode or with a process that modifies the file in some way, the file remains on your local file system as either a resident or premigrated file, depending on the actions that the other process takes.

command
A command and any of its valid arguments for which you want the specified execution mode to remain in effect. If you do not specify a command, the HSM client starts a new shell. The shell that is started is the one that you specified as your default shell in/etc/passwd. The execution mode that you specify remains in effect until you exit the shell.

Examples

Task Command
Display the current execution modes. dsmmode
Change the data access mode for a grep command to ensure that only resident and premigrated files are searched, and migrated files are not accessed and recalled. dsmmode -Dataaccess=z grep \ spaceman *


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