Avamar: Information about Avamar NDMP backups and NAS streams and best practices

Summary: Avamar Network Data Management Protocol (NDMP) uses one stream per volume. v6.0 supports 4, v7.0 supports eight streams. VNX, NetApp, Celerra 4 streams (VNX default is four but may support eight streams depending on memory on data mover); Isilon 8. Best practice: minimize clients, run largest backups first. ...

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Instructions

Avamar Network Data Management Protocol (NDMP) Backup and NAS Stream Best Practices

General Guidelines
  • Minimize the number of clients used for backups.
  • Maximize the number of volumes in a dataset so Avamar can keep streams busy.
  • Avamar starts backups in size order, largest first.
  • Only one client instance can run at a time.
  • Balance the number of active clients with the number of available streams.
  • Do not overload a Datafiler; they are limited to four streams by default.
  • When using multiple NDMP accelerator nodes, consider adding additional Datafilers to avoid overload.
  • Plan for other programs or backups that consume NDMP streams to maintain reliability and efficiency.

Device Stream Capacities

Caution: Exceeding the supported stream count on any device can cause backup failures or degraded performance. Verify device capabilities before configuring additional streams.
 
Device Type Supported Streams Notes
VNX (standard) 4 The default is 4; verify with VNX administrator if 8 are supported.
VNX (newer, larger memory) 8 Eight streams are supported when memory permits.
Celerra 4 Only four streams are supported.
Isilon 4 per node No physical limitation, but excessive streams may exhaust memory.
NetApp 4 per datamover Four streams per datamover


A stream is a connection between an Avamar NDMP accelerator node and a Network Attached Storage device (NAS).

With Avamar NDMP, each volume/target uses 1 and only one stream.

Avamar Version 7.0 and newer
  • NDMP clients can support eight streams
  • Each 32GB RAM Avamar NDMP accelerator can support at least eight streams.
  • Each stream provides typical performance of roughly 2GB per sec

 

Affected Products

Avamar

Products

Avamar, Avamar Plug-in for NDMP
Article Properties
Article Number: 000019976
Article Type: How To
Last Modified: 19 Mar 2026
Version:  6
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