Environment variables are used to communicate information about a backup or restore operation between an NDMP-enabled backup application and a filer. For example, if a user specifies that a backup application should back up /vol/vol0/etc, the backup application sets the FILESYSTEM environment variable to /vol/vol0/etc. Similarly, if a user specifies that a backup should be a level-1 backup, the backup application sets the LEVEL environment variable to 1 (one).
A backup administrator rarely specifies environment variables; however, you might want to change the value of an environment variable from that set by the backup application to characterize or work around a functional or performance problem. For example, an administrator may want to temporarily disable file history generation to determine if the backup application's processing of file history information is contributing to performance issues or functional problems.
Many backup applications provide a means to override or modify environment variables or to specify additional environment variables. See your backup application documentation for information.
The following table contains descriptions of what the environment variables supported by Data ONTAP do if they are used. The default values listed in the table are set by Data ONTAP and might be modified by your backup application. If you modify manually the values set by the backup application, as needed for it to work properly, the application might behave unpredictably because the dump or restore operations might not be doing what the backup application expected them to do. But in some cases, judicious modifications might help in identifying or working around problems.
Environment Variable
|
Valid Values
|
Default
|
Description
|
|---|
ACL_START
|
return only
|
none
|
Created by the backup operation, the ACL_START variable is an offset value used by a direct access restore or restartable NDMP backup operation. The offset value is the byte offset in the dump file where the ACL data (Pass V) begins and is returned at the end of a backup. For a direct access restore operation to correctly restore backed up data, the ACL_START value must be passed to the restore operation when it begins. An NDMP restartable backup operation uses the ACL_START value to tell the backup application where the nonrestartable portion of the backup stream begins.
|
BASE_DATE
|
0, -1, or DUMP_DATE value
|
-1
|
Specifies the start date for incremental backups. There is no equivalent option for the dump command. When set to -1, the BASE_DATE incremental specifer is disabled. When set to 0 on a level 0 backup, incremental backups are enabled. Subsequent to the initial backup, the value of the DUMP_DATE variable from the previous incremental backup is assigned to the BASE_DATE variable. These variables are an alternative to the /etc/dumpdates file for controlling incremental backups.
|
DATA_BLOCK_SIZE
|
4-64
|
63
|
Specifies the tape blocking factor in kilobytes.
|
DEBUG
|
Y or N
|
N
|
Specifies that debugging information is printed. Debug information is not printed if only the VERBOSE variable is set. The messages printed when the DEBUG or VERBOSE variables are set are mutually exclusive, debug messages are not a superset of verbose messages and vice versa. There is no equivalent option for the dump or restore command.
|
DIRECT
|
Y or N
|
N
|
Specifies that a restore should fast-forward directly to the location on the tape where the file data resides instead of scanning the entire tape. For direct access restoration to work, the backup application must provide positioning information; therefore, you would rarely modify the DIRECT variable. If you specified the value Y, the backup application would specify the file or directory names and the positioning information in its nlist. The nlist information cannot be modified by changing environmental variable values.
|
DMP_NAME
|
string
|
none
|
Specifies the name for a multiple subtree backup. The DMP_NAME variable is equivalent to the n option of the dump command. This variable is mandatory for multiple subtree backups.
|
DUMP_DATE
|
return value
|
none
|
You do not change this variable directly. It is created by the backup if the BASE_DATE variable is set to a value other than -1. The BASE_DATE variable is derived by prepending the 32-bit level value to a 32-bit time value computed by the dump software. The level is incremented from the last level value passed into the BASE_DATE variable. The resulting value is used as the BASE_DATE value on a subsequent incremental backup.
|
ENHANCED_DAR_
ENABLED
|
Y or N
|
N
|
Specifies if enhanced Direct Access Restore (DAR) functionality is instantiated. Enhanced functionality consists of support for directory DAR, DAR of files with NT Streams, and capacity and performance improvements. The ENHANCED_DAR_ENABLED variable is not checked at the beginning of a backup and, for correct operation, should not be set. Enhanced DAR is instantiated with a T value, not Y, at the conclusion of a backup only if the following is true:
- Data ONTAP supports enhanced DAR (Data ONTAP 6.4 or later)
- File history is enabled (HIST=Y)
- Creation of enhanced DAR information on the dump file completed successfully
When restoring, the value that was returned by the Data Get Environment NDMP protocol message after the backup is passed to the restore operation.
If you want to disable the enhanced DAR features when restoring data, set the ENHANCED_DAR_ENABLED variable to F or N.
Note
You must not set the ENHANCED_DAR_ENABLED variable to T when restoring data if enhanced DAR was not instantiated because the data to support enhanced DAR is not on the dump file. |
EXCLUDE
|
pattern string
|
none
|
Specifies files or directories that are excluded when backing up data. The EXCLUDE variable is equivalent to the X option of the dump command. The exclude list is a comma-separated list of file or directory names. If the name of a file or directory matches one of the names in the list, it is excluded from the backup. The following are rules for specifying names in the exclude list:
- The exact name of the file or directory must be used.
- An asterisk (*) is a wildcard character. The asterisk must be either the first or the last character of the string. Each string can have up to two asterisks.
- A comma in a file or directory name must be preceded with a backslash.
- The exclude list can contain up to 32 names.
|
EXTRACT
|
Y or N
|
N
|
Specifies that subtrees of a backed-up dataset are to be restored. The EXTRACT variable is equivalent to the x option of the restore command. The backup application specifies in the nlist the names of the subtrees to be extracted. If a file named in the nlist matches a directory whose contents were backed up, the directory is recursively extracted.
|
EXTRACT_ACL
|
Y or N
|
Y
|
Specifies that ACLs from the backed up file are restored on a restore operation. The EXTRACT_ACL variable is equivalent to the A option of the restore command. The default is to restore ACLs when restoring data, except for direct access restores (DIRECT=Y).
|
FILESYSTEM
|
string
|
None
|
Specifies the pathname of the root of the data that is being backed up. For example, /vol/vol0/etc.
|
FORCE
|
Y or N
|
N
|
Specifies that a restore operation continues, regardless of inode limitations. The FORCE variable is equivalent to the F option of the restore command. When this variable is set to N, if the restore operation determines that there are fewer free inodes than the number of files it needs to create, it aborts. Setting the variable to Y causes the restore operation to proceed on the assumption that new files overwrite older files and that the file system will not run out of inodes. If the restore operation runs out of inodes, the restore operation aborts during its run.
|
HIST
|
Y or N
|
N
|
Specifies that file history information is sent to the backup application. Most commercial backup applications set the HIST variable to Y. If you want to increase the speed of a backup operation, or you want to troubleshoot a problem with file history collection, you can set this variable to N.
Note
You should not set the HIST variable to Y if the backup application does not support file history. |
IGNORE_CTIME
|
Y or N
|
N
|
Specifies that a file is not incrementally backed up if only its ctime value has changed since the previous incremental backup. Some applications, such as virus scanning software, change the ctime value of a file within the inode, even though the file or its attributes have not changed. As a result, an incremental backup might back up files which have not changed. The IGNORE_CTIME variable should be specified only if incremental backups are taking an unacceptable amount of time or space because the ctime value was modified.
|
IGNORE_QTREES
|
Y or N
|
N
|
Specifies that the restore operation does not restore qtree information from backed up qtrees. The IGNORE_QTREES variable is equivalent to the Q option of the restore command.
|
LEVEL
|
0-9
|
0
|
Specifies the backup level. Level 0 copies the entire dataset. Incremental backup levels, specified by values above 0, copy all files new or modified since the last incremental backup. For example, a level 1 backs up new or modified files since the level 0 backup, a level 2 backs up new or modified files since the level 1 backup, and so on.
|
LIST
|
Y or N
|
N
|
Specifies that backed-up file names and inode numbers are listed as they are restored. The LIST variable is equivalent to the t option of the restore command.
|
LIST_QTREES
|
Y or N
|
N
|
Specifies that backed-up qtrees are listed as are restored. The LIST_QTREES variable is equivalent to the T option of the restore command.
|
MULTI_SUBTREE_
NAMES
|
string
|
none
|
Specifies that the backup is a multiple subtree backup. The MULTI_SUBTREE_NAMES variable is equivalent to the l option of the dump command. Multiple subtrees are specified in the string which is a newline-separated, null-terminated list of subtree names. Subtrees are specified by path names relative to their common root directory, which must be specified as the last element of the list. If you use this variable, you must also use the DMP_NAME variable.
|
NDMP_UNICODE_
FH
|
Y or N
|
N
|
Specifies that a Unicode name is included in addition to the NFS name of the file in the file history information. This option is not used by most backup applications and should not be set unless the backup applciation is designed to receive these additional file names. The HIST variable must also be set.
|
NDMP_VERSION
|
return only
|
none
|
You should not modify the NDMP_VERSION variable. Created by the backup operation, the NDMP_VERSION variable returns the NDMP version. Data ONTAP sets the NDMP_VERSION variable during a backup for internal use and to pass to a backup application for informational purposes. The NDMP version of an NDMP session is not set with this variable.
|
NO_ACLS
|
Y or N
|
N
|
Specifies that Access Control Lists (ACLs) are not copied when backing up data. The NO_ACLS variable is equivalent to the A option of the dump command. Ordinarily a backup using the dump command writes out metadata related to Windows ACLs. The NO_ACLS variable stops this information from being backed up.
|
NON_QUOTA_TREE
|
Y or N
|
N
|
Specifies that files and directories in qtrees are ignored when backing up data. The NON_QUOTA_TREE variable is equivalent to the Q option of the dump command. When set to Y, items in qtrees in the dataset specified by the FILESYSTEM variable are not backed up. This variable has an effect only if the FILESYSTEM variable specifies an entire volume. The NON_QUOTA_TREE variable only works on a level-0 backup and does not work if the MULTI_SUBTREE_NAMES variable is specified.
|
NOWRITE
|
Y or N
|
N
|
Specifies that the restore operation does not write data to the disk. The NOWRITE variable is equivalent to the N option of the restore command. This variable is used for debugging.
|
REPLICATE
|
Y or N
|
N
|
Specifies an unlimited number of incremental backups. There is no equivalent option for the dump command. The REPLICATE variable is ignored when the BASE_DATE and DUMP_DATE variables are used to manage incrementals.
|
RESTART
|
Y or N
|
N
|
Not supported by NDMP software; the RESTART variable is ignored.
|
UPDATE
|
Y or N
|
N
|
Specifies that the dumpdates file is updated after backing up data. The UPDATE variable is equivalent to the u option of the dump command. When set to Y, the /etc/dumpdates file (used for managing incremental backups) is updated after a successful backup.
|
VERBOSE
|
Y or N
|
N
|
Specifies that detailed information about dump and restore operations is printed. The VERBOSE variable is equivalent to the v option of the dump and restore commands.
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