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Difference between Label and erase in netbackup

H_Sharma
Level 6

Hello Experts,

Pls let me know the difference between Label and erase in netbackup

Pls also let me know when to use label and erase.

1 ACCEPTED SOLUTION

Accepted Solutions

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

Have you tried the explanations in NetBackup Administrator's Guide, Volume I  ?

Table 8-14 Types of erase

SCSI long erase:
Rewinds the media and the data is overwritten with a known data pattern. A SCSI long erase is also called a secure erase because it erases the recorded data completely.
Note: A long erase is a time-consuming operation and can take as long as two hours to three hours. For example, it takes about 45 minutes to erase a 4-mm tape on a standalone drive

SCSI quick erase:
Rewinds the media and an erase gap is recorded on the media. The format of this gap is drive dependent. It can be an end-of-data (EOD) mark or a recorded pattern that the drive does not recognize as data.
Some drives do not support a quick erase (such as QUANTUM DLT7000). For the drives that do not support a quick erase, the new tape header that is written acts as an application-specific quick erase.

About labeling NetBackup volumes
When NetBackup labels a volume, it writes a record on the magnetic tape of the volume; the record (or label) includes the NetBackup media ID.
Normally, NetBackup controls the labeling of its volumes. In most cases, NetBackup labels a volume the first time it is used for a backup.
The volume label depends on whether or not the media has a bar code, as follows: 
■ If the robot supports bar codes and the media has bar codes, NetBackup uses the last six characters of the bar code for the media ID.
To change this default action, specify and select specific characters by using
Media ID generation rules.
See “Configuring media ID generation rules” on page 442.
■ For volumes without bar codes, by default NetBackup uses a prefix of the letter
A when it assigns a media ID to a volume (for example, A00001).
To change the default prefix, use the MEDIA_ID_PREFIX configuration option in
the vm.conf file.

 

Normally not needed to do ANY of these.
NBU will automatically write the volume label first time a tape is used for backup.

Media can be erased when you want to get rid of old media to ensure data cannot be read by anyone.

Manual labeling is needed when you use standalone tape drives and for some VTLs to reclame space.

 

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4 REPLIES 4

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

Have you tried the explanations in NetBackup Administrator's Guide, Volume I  ?

Table 8-14 Types of erase

SCSI long erase:
Rewinds the media and the data is overwritten with a known data pattern. A SCSI long erase is also called a secure erase because it erases the recorded data completely.
Note: A long erase is a time-consuming operation and can take as long as two hours to three hours. For example, it takes about 45 minutes to erase a 4-mm tape on a standalone drive

SCSI quick erase:
Rewinds the media and an erase gap is recorded on the media. The format of this gap is drive dependent. It can be an end-of-data (EOD) mark or a recorded pattern that the drive does not recognize as data.
Some drives do not support a quick erase (such as QUANTUM DLT7000). For the drives that do not support a quick erase, the new tape header that is written acts as an application-specific quick erase.

About labeling NetBackup volumes
When NetBackup labels a volume, it writes a record on the magnetic tape of the volume; the record (or label) includes the NetBackup media ID.
Normally, NetBackup controls the labeling of its volumes. In most cases, NetBackup labels a volume the first time it is used for a backup.
The volume label depends on whether or not the media has a bar code, as follows: 
■ If the robot supports bar codes and the media has bar codes, NetBackup uses the last six characters of the bar code for the media ID.
To change this default action, specify and select specific characters by using
Media ID generation rules.
See “Configuring media ID generation rules” on page 442.
■ For volumes without bar codes, by default NetBackup uses a prefix of the letter
A when it assigns a media ID to a volume (for example, A00001).
To change the default prefix, use the MEDIA_ID_PREFIX configuration option in
the vm.conf file.

 

Normally not needed to do ANY of these.
NBU will automatically write the volume label first time a tape is used for backup.

Media can be erased when you want to get rid of old media to ensure data cannot be read by anyone.

Manual labeling is needed when you use standalone tape drives and for some VTLs to reclame space.

 

RamNagalla
Moderator
Moderator
Partner    VIP    Certified

 

see page number 471 in admin guide

About labeling NetBackup volumes
When NetBackup labels a volume, it writes a record on the magnetic tape of the
volume; the record (or label) includes the NetBackup media ID.
Normally, NetBackup controls the labeling of its volumes. In most cases, NetBackup
labels a volume the first time it is used for a backup.
The volume label depends on whether or not the media has a bar code, as follows:
■ If the robot supports bar codes and the media has bar codes, NetBackup uses
the last six characters of the bar code for the media ID.

To change this default action, specify and select specific characters by using
Media ID generation rules.
See “Configuring media ID generation rules” on page 442.
■ For volumes without bar codes, by default NetBackup uses a prefix of the letter
A when it assigns a media ID to a volume (for example, A00001).
To change the default prefix, use the MEDIA_ID_PREFIX configuration option in
the vm.conf file.
See the NetBackup Administrator’s Guide, Volume II.
Media is not labeled automatically in the following situations:
■ They were last used for NetBackup catalog backups.
Do not label catalog backup volumes unless they are no longer used for catalog
backups.
■ They contain data from a recognized non-NetBackup application and NetBackup
is configured to prohibit media overwrite for that media type.
To label these media types, the following must be true:
■ NetBackup has not assigned the media
■ The media contains no valid NetBackup images

 

Erasing a volume
You can erase the data on a volume if the following are true:
■ The volume is not assigned.
■ The volume contains no valid NetBackup images.
After NetBackup erases the media, NetBackup writes a label on the media.
If you erase media, NetBackup cannot restore or import the data on the media.
If a volume contains valid NetBackup images, deassign the volume so NetBackup
can label it.
See “About deassigning volumes” on page 460.

Nicolai
Moderator
Moderator
Partner    VIP   

Label = overwrite the allocation table of the tape (aka VTOC or FAT)

Erase = write 0 or 1 on the entire tape.

Normal a label do the job if you want to erase the tape from previous content. 

mph999
Level 6
Employee Accredited

I believe a scsi long erase is actually up to the drive, so different drives may do different things.