Data Backup and Recovery

NDMP Backup Issues


We recently upgraded to ONTap 8.2.3P3, but found that the restrictions with only 4 sessions for NDMP was causing us issues. We have 400+ sessions ordinarily, and when we were down to 4 sessions, it was taken over 7 days to secure the data. Daily backups had to be monitored to get the majority of backups through (NetBackup).


So, we decided to revert back to 8.1.4P1 (previous version).

Now, we have the NDMP functionality, but have lost the ability to snapmirror from 8.2.3P3 source to 8.1.4P1 destination.


I have left the replicated volumes alone, as that is our only point in time copy. We have around 20Tb to replicate, and only have 15Tb free, leaving the replicated volumes in place.


Is there a way to replicate from 8.2.3P3 to 8.1.4P1, using QSM, or even snapvault ?.


I don't want to upgrade again to 8.2.3P3 just to overcome the snapmirror issue, and sacrifice NDMP, as we need to get this data onto tape, and offsite due to regulatory requirements.


I have an option where I could back up the data via NFS mount points, but these are standard backups, and I cannot use Storage Lifecycle Policies.





The maximum number of NDMP sessions depends on the system memory of a storage system,


If System memory of a storage system       Maximum number of NDMP sessions


< 16GB                                                                               8


Greater than or equal to 16GB but less than

24GB                                                                                   20


Greater than or equal to 24Gb                                           36



For more details please refer below link  Data Protection Tape Backup and Recovery Guide,Clustered Data ONTAP  8.2, page no 41,






If this post resolved your issue, help others by selecting ACCEPT AS SOLUTION or adding a KUDO.


Thanks, have seen that.

We have 4 because our filer has 12Gb.


The 8 sessions - is 4 for backup, and 4 for restore, but you cannot internix them.


We have over 400 sessions, just for backups, so doesn't really aid the situation, and previously was 136.

I cannot seen anything that needs to be down factored by 34 times, quite like NDMP has.

All I have been told, is that NDMP now needs more memory, but not how much, and why, and where it has been taken given to, and why other areas such as snapmirror have not been compromised, just NDMP.