On Demand Only

[belse]

What is On Demand Only in netbackup? and When should we use on demand only in netbackup?

[Ashish-Sharma]

On demand only storage unit setting on Windows

The On demand only storage unit setting specifies whether the storage unit is available exclusively on demand - that is, only when a policy or schedule is explicitly configured to use this storage unit. Uncheck On demand only to make the storage unit available to any policy or schedule.

For SnapVault and NearStore storage units, On demand only is selected by default and cannot be changed.

Note:

If On demand only is selected for all storage units, be sure to designate a specific storage unit for each policy or schedule. Otherwise, NetBackup is unable to find a storage unit to use.

http://www.symantec.com/business/support/index?page=content&id=HOWTO34413

[Andy_Welburn · Accepted solution]

Hmmmmmm.....

From the context sensitive help in the GUI (storage units):

The On demand only setting specifies whether the storage unit is available exclusively on demand. That is, only when a policy or schedule is explicitly configured to use this storage unit. Clear the On demand only check box to make the storage unit available to any policy or schedule.

For SnapVault and NearStore storage units, On demand only is selected by default and cannot be changed.

Caution: If On demand only is selected for all storage units, be sure to designate a specific storage unit for each policy or schedule. Otherwise, NetBackup is unable to find a storage unit to use.

........ so a STU set as  'on demand only' will only be used when a policy/schedule is set to specifically use (demand) it!

[belse]

Thanks Ashish and Andy for your reply........ Any Examples???????????

[Andy_Welburn]

Not personally!

Generally, or historically, we have put all our disk based STUs as on demand only & specified in policy & our tape based not on demand only, but still specified in the policy.

Do not remember utilising the 'Any Available' storage unit a great deal but then our environment is small compared to some.

If you had a large mix of policies & stu's with 'any available' in the mix but only wanted specific policies to use a specific tape or disk based stu (media density incompatiblities maybe or disk locations or other environmental or resource restrictions) then using the 'on demand only' would be useful there.

If you have several stu's with 'on demand only' *not* selected & 'Any Available' set in your policies then those policies backups can essentially use any of those stu's.

I would imagine that this would be most beneficial in larger environments &/or those with more restrictive resource requirements - but we haven't so I can only generalise!

[Marianne]

Examples: 

Disk STU should always have On Demand Only selected.
With Disk, the backup admin wants to control which backups are sent to disk because disk space is ALWAYS limited - even when Dedupe disk is used.

SAN Media Server STU must have On Demand Only selected.
SAN Media server can only backup itself. If STU is configured without this option selected, STU creation will fail with status 159 (licensed use has been exceeded).