NetApp Backup: NDMP Vs. Cloud

Author:  Jeff Whitehead, CTO, Co-founder, Zetta.net

NetApp filers are versatile and high-performance storage appliances. They’re so reliable that it’s easy to forget things can go wrong – like a fire, theft, or major storm. The potential for an unknown disaster is what makes offsite backup a necessity, even for NetApp filers with internal redundancy.

NetApp Backup With NDMP

The traditional methods of backing up a NetApp – an NDMP dump of the WAFL file system – works, but it has a number of shortcomings:
 
• You Need a 2nd NetApp To Recover – since the NDMP dump is a binary image of the WAFL file system, the only device that can parse and utilize this image is another NetApp.
 
• Testing Requires Unutilized NetApp Storage – many environments only have a single filer, and even large environments tend to not have a “spare” NetApp just lying around, and this makes it difficult to perform recovery testing.
 
• Untested Backups Aren’t Valid – It has long been a truism of enterprise data management that “a backup isn’t a valid backup, until it has been restored and tested.”
 
This doesn’t necessarily mean that every single backup has to be recovered, but quarterly testing is prudent, and anything less than annual recovery can be considered very risky.

Cloud-based NetApp Offsite Backup

Zetta DataProtect for NetApp overcomes the limitation of a proprietary data dump with open replication technology – Zetta provides a managed and integrated solution that replicates the data in its original format (files and folders, with ACLs* and other metadata preserved) in enterprise-grade storage systems hosted in Zetta’s data centers.

How it works:
 
1. ZettaMirror is installed on a gateway server, Linux, or Windows PC, that has NFS or CIFS access to the NetApp filer**.
 
2. On a schedule, configured via the SMP ZettaMirror wakes up, makes a control connection to the NetApp Filer, and creates a snapshot.
 
3. ZettaMirror reads the newly created snapshot, looking for files that have changed since the previous sync.
 
4. When it detects files that have changed, it further inspects the file and finds just the portions of the file that have changed since the previous sync, and transmits just those changes.
 
5. When the sync has completed, it signals the cloud data center to create a snapshot, and removes the snapshot created on the local filer.
 
The end result is a snapshot in Zetta’s data centers that’s identical in content to the source snapshot. Additionally, since updates are applied at a sub-file level, these snapshots are space efficient (similar to snapshots on a NetApp).
 
The versions of customer data backed up at Zetta can be accessed online worldwide via a standard web browser, mounted as a web drive, or restored via ZettaMirror to a NetApp filer or – crucially – any other device.
 
Zetta DataProtect for NetApp provides many of the benefits of SnapMirror for offsite disaster recovery, without the cost of a second filer and second data center.
 
* The style of ACL depends on the client you use — those using qtree/NTFS ACLs should use a Windows client/CIFS to preserve them. Standard POSIX ACLs/NFS would be best served with a Linux client.
 
** A high capacity, low latency connection is preferred. A standard 1Gbps ethernet connection within a corporate LAN works for most cases, but 10Gbps or multiple gateway devices would be warranted for very large file systems. Ping times between the ZettaMirror host and the NetApp filer should be < 1-3ms for best performance. This gateway system needs the ability to make outbound HTTPS connections to Zetta's datacenters.

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Jeff Whitehead is co-founder and CTO of Zetta. Previously, as CIO of Shutterfly, he successfully managed over six petabytes of storage infrastructure.

URLs embedded in this article 

• Zetta.net Simplifying Backups: http://bit.ly/YdnT3N

• Zetta DataProtect for NetApp:  http://www.zetta.net/netapp/

• ZettaMirror:   http://www.zetta.net/zettaMirror.php