Using Server-to-Server Synchronization FAQ

Q. What is Server-to-Server Synchronization?
A.
Server-to-Server Synchronization (S2S) is a Java technology-based SnapExtension that copies the contents of a shared volume on a source Snap Server to one or more destination Snap Servers.

Q. What are the benefits of S2S?
A.
Time-to-data advantage in the event of a server failure.
Should the source server fail, any networked client can quickly access the data on the destination server, either locally or over the Internet, resulting in little downtime or loss of productivity. Once a replacement Snap Server becomes available, a synchronization between the destination Snap Server and the replacement Snap Server can quickly and easily restore the user’s data.
Data availability during routine maintenance.
In the event that the source Snap Server needs routine maintenance such as a software upgrade, the administrator can simply initiate a manual failover to the destination server. User access to data remains available on the network throughout the maintenance process.

Q. How does S2S work?
A. 
S2S is managed through the Web-based user interface that allows synchronizations to be performed manually or on a regularly scheduled basis. The initial synchronization creates a share level (as opposed to directory or file level) copy of all files and directories on the destination Snap Server(s). Subsequent synchronizations will copy only those files that have been modified since the last synchronization. Some third party applications may lock file access, therefore it is recommended that synchronizations be scheduled for non-peak hours.

Q. Is S2S a one-way or two-way sync?
A. 
S2S is a one-way sync with a designated source and destination. Any files that are deleted on the source server will be deleted from the destination server(s) during subsequent synchronizations, as will files that are manually copied to the destination server share.

Q. What hardware and software are required to run S2S?
A. 
Minimum requirements include two Snap Servers and two licensed copies of S2S. Any Snap Server 12000, 4100, 2200 or 2000 unit will work with S2S.

Q. Can different capacity Snap Servers utilize S2S?
A. 
Yes, Snap Servers of different capacities can utilize S2S provided there is sufficient capacity on the destination server to accommodate the source share being synchronized. For example, S2S could be used to back up multiple Snap Server 4100 units to a Snap Server 12000.

Q. How does the one-to-many sync work?
A. 
One-to-many synchronizations are serially completed (changed files are copied first to target server one, then to server two, etc.)

Q. Will S2S work across a Wide Area Network (WAN)?
A. 
S2S will work across a WAN. However, the speed of the WAN link will dictate the performance.

Q. Does S2S replace regular backup and/or disaster recovery?
A. 
S2S allows quick access to data in the event of a source server failure. Regular backups of critical data to tape or alternate media are still recommended.

Q. Is the sync incremental?
A. 
With the exception of the first complete sync or backup, every S2S sync is incremental and only copies files that have been changed since the last synchronization.

Q. Is the sync on a file-by-file or block-by-block basis?
A. 
S2S syncs are performed on a file-by-file basis.

Q. How is S2S different from mirroring?
A. 
Mirroring is defined as copying data from one storage device to another in real time. S2S allows for manual and scheduled synchronizations but does not permit continuous synchronizations in real time.