NDMP Backups are failing with a Warning : NDMP backup/restore streams reach the configured concurrent streams 4, but less than the maximum supported concurrent streams 8.

NDMP Backups are failing with a Warning : NDMP backup/restore streams reach the configured concurrent streams 4, but less than the maximum supported concurrent streams 8.

Article: 100006717
Last Published: 2020-07-30
Ratings: 0 0
Product(s): NetBackup

Problem

During a backup job operation, the following message are reported to NetBackup Job Details from a EMC Celerra Filer

"Active NDMP backup/restore streams reach the maximum concurrent streams supported 8. No more NDMP sessions can be started. Wait current backup/restore sessions finish before start new ones."

The active job will immediately fail with Exit Status Codes 25 or 99.

When backing up a EMC Celerra device that has been configured with a vast number of filesystems that have been defined within one single policy, and the 'Allow Multiple Streams' option is enabled, this will initiate a number of streams (one stream per filesystem)

The failures reported to NetBackup are caused by the streams limit of 4 that is defined by the EMC Celerra Host.

Error Message

NetBackup Job detailed status and may fail with Exit Status Codes 25 or 99.

From Activity Monitor > Jobs > Detailed Status :

Exit Status Codes 25 Failure

25/08/2019 12:00:02 - begin writing
25/08/2019 12:00:02 - Error ndmpagent (pid=7020) filername: Active NDMP backup/restore streams reach the maximum concurrent streams supported 8. No more NDMP sessions can be started. Wait current backup/restore sessions finish before start new ones.
25/08/2019 12:00:03 - Error ndmpagent (pid=7020) ndmp_data_connect_v3 failed, status = -1 (-1)
25/08/2019 12:00:03 - Error ndmpagent (pid=7020) NDMP backup failed, path = /volume/dir/
25/08/2019 12:00:04 - Info bpbrm (pid=6636) child done, status 25
25/08/2019 12:00:04 - Info bpbrm (pid=6636) sending message to media manager: STOP BACKUP filername_1413000000
25/08/2019 12:00:05 - Info bpbrm (pid=6636) media manager for backup id filername_1413000000 exited with status 0: the requested operation was successfully completed
25/08/2019 12:00:05 - end writing; write time: 0:00:03
cannot connect on socket (25)

NDMP backup failure(99) Failure

25/08/2019 12:51:51 - Info bptm(pid=9316) start backup
25/08/2019 12:51:52 - Error ndmpagent(pid=8772) NDMP_LOG_ERROR 0 Active NDMP backup/restore streams reach the configured concurrent streams 4, but less than the maximum supported concurrent streams 8. No more backup/restore sessions can be started. Wait current backup/restore sessions finish, then increase concurrent DataStreams parameter.
25/08/2019 12:51:53 - begin writing
25/08/2019 12:51:53 - Error ndmpagent(pid=8772) ndmp_data_connect_v3 failed, status = -1 (-1)
25/08/2019 12:51:53 - Error ndmpagent(pid=8772) NDMP backup failed, path = /volume/dir/
25/08/2019 12:51:59 - end writing; write time: 00:00:06
NDMP backup failure(99)

Cause

This reported failures are caused by the concurrent streams limit of 4 that is defined by EMC Celerra Host.

And by default each a Data Mover (individual data movers map network and storage connectivity in the Celerra) which supports a total of 4 NDMP sessions

Solution

A workaround to Netbackup and adjust the "Limit Jobs Per Policy"  by setting the count to 4 from the 'Policy Attributes Tab' 

By lowering the concurrency to 4 jobs should allow for "NDMP sessions on the Celerra " to become active, and the remaining jobs will queue until such time any inflight NDMP session are marked complete.

If a EMC Celerra device has a minimum of 8GB memory, then it is possible to adjust the NDMP sessions count to 8

Celerra command example:

#  server_param server_xx –facility NDMP –modify concurrentDataStreams –value 8

Applies To:

EMC Celerra

Please Consult the most current "Configuring NDMP backups on Celerra" documentation from EMC.

 

 

 

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