NDMP Backup options Isilon

Hi @Marcel Krommenhoek , thanks for the post!

To confirm, you’re referring to the underscores vs. the colons?

Any chance any of your cases with CV support are still open?  If not, open a new case (share the number here so I can track it) so our dev team can look into it closer.

I’m not aware of this, though a deeper dive is best here.

What’s the actual issue with the NDMP backups though? These fields I believe will change with each job as I believe they refer to some of the job parameters. 

I had the same issue (and probably reached the same person at Dell support). In our scenario there was an anomalous high CPU condition on the Isilon that went away after a week and nothing had to be changed with our backup config. In the meantime the case got escalated and both Commvault and Isilon engineering got engaged and luckily have a good working relationship. I am pasting in the conclusions we got in case this helps anyone else.

General summary (Isilon NDMP backups using Commvault)
 
There are 2 backup methods for NDMP Incremental backups - Timestamp and Snapshot. Both methods are fully supported by both vendors and both methods work equally well for general workloads. The default setting in Commvault is Snapshot (as set with the "Fast Incremental (Use Snapshot for Backup)" checkbox. Changing the setting does not take effect until a Full backup is run. Alternating between settings should not have downstream impacts for Commvault - deduplication, retention, etc should be the same. 
 
There are two main considerations between the two methods. In environments with high daily change rates (over 2-3%) the Timestamp method is more efficient. In these cases Snapshots use more resources since Snapshot backups require taking and comparing differences between 2 snapshots in memory and this can take longer when there is more data to process. Alternately, with smaller change rates Snapshot backups can be faster since Isilon can efficiently identify the small number of file changes between two snapshots whereas in a Timestamp backup the Isilon needs to evaluate all files to determine what changes occurred since the base time. Dell is seeing more customer with higher change rates so Timestamp should be strongly considered as an alternative to the default setting.
 
Although the Commvault default is to use Snapshots, if the Snapshot backup fails for any reason the Isilon will automatically switch over and provide a “token based incremental” Timestamp backup instead. 
 
When using Snapshot Incremental backups there are additional granular parameters that can also be changed but are not usually exposed settings. Although obscure, these settings have led to misunderstandings by the respective vendor support teams. Commvault software is coded to pass the parameter "2" but there have been circumstances where customers have been asked to use option "7" instead. After reviewing with both vendors we came to the following joint understandings
- Dell agrees that both option 2 and option 7 are valid and fully supported
- Commvault can provide customers with an Additional Setting that causes Commvault to use Option 7 instead of the default
- Option 2 was selected as the default because it leaves only the prior snapshot from the last successful backup thus conserving Isilon resources while option 7 may keep an unlimited number of snapshots.
- Option 2 depends on agreement between Commvault and Isilon on Snpashot timestamps. In cases where there is a mismatch the fallback process would run a timestamp based incremental which can take more time than a snapshot based incremental if the data change rate is low or less time if the change rate is higher. Generally, option 2 is recommended unless there is a backup scenario that requires the additional snapshots.