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This directory contains disk systems intended as targets for backups. There is a separate directory for disk targets for archives.

Note: IBM announced 4/17/08 that they are purchasing Diligent. This makes the future of the current IBM product (based on Falconstor) and the HDS product (based on Diligent) unclear. While both vendors have stated that they will continue to support existing customers, it is unclear how this will affect long term viability of these products.


Vendor/Product Original Vendor VTL, NAS,
or Local
Integrated or
Standalone
Appliance,
Gateway,
or Software
De-dupe Inline or
Post-process
Dedupe Domain Dedupe Method OST Deduped
Replication
See definitions of these column names
COPAN FS=COPAN
VTL=Falconstor
VTL & NAS Integrated Appliance On VTL Post-process Global Hash Yes Yes
Data Domain Data Domain VTL & NAS Standalone Appliance & Gateway Yes Inline Local Hash Yes Yes
EMC 3D 1500/3000 Quantum VTL,NAS Integrated Appliance Yes Both Local Hash Yes Yes
EMC 3D 4000 Quantum VTL Integrated Appliance Yes Post-process Local Hash No Yes
EMC Avamar Avamar VTL & NAS Standalone Appliance & Software Yes Inline Global ? ? Yes
EMC EDL Falconstor VTL Integrated Appliance No N/A N/A N/A ? No
Exagrid Exagrid NAS N/A Appliance Yes Inline Global Delta Diff No Yes
Falconstor Falconstor VTL Integrated Software Yes Post-process Global Hash Yes Yes
Gresham Clarita VTL Gresham Integrated Software No N/A N/A N/A N/A ? No
Fujitsu-Siemens CentricStor Fujitsu-Siemens Integrated Appliance No N/A N/A N/A N/A ? No
HDS VTL ? ? ? ? ? ? ? ? ? ?
HP VTL SEPATON VTL Standalone Appliance Yes Post-process Global Delta Diff No No
IBM VTL Diligent (IBM) VTL Standalone Appliance Yes Inline Global (2 nodes) Delta Diff No Storage-
based
NEC Hydrastor NEC NAS N/A Software Yes Inline Global Hash No Yes
NetApp Nearstore VTL NetApp VTL Integrated Appliance Yes Post-process Local Delta Diff No No
NetApp NearStore NetApp NAS N/A Appliance Yes Post-process Local to Flex-vol Hash + bit compare No Yes
NetZerver FileZerver NetZerver NAS Standalone Appliance Yes Inline Global Hash
File redundancy
No Storage-
based
Overland Reo Diligent VTL Standalone Appliance Yes Inline Local Delta Diff No Storage-
based
Quantum DXi Quantum VTL, NAS Integrated Appliance Yes Both Local Hash Yes Yes
SEPATON SEPATON VTL Standalone Appliance Yes Post-process Global Delta Diff + others No No
PureDisk Storage Unit
(Only works with NBU)
Symantec LFS N/A Software Yes Inline Local Hash Yes Yes
Sun StorageTek VTL Falconstor VTL Integrated Appliance Yes Post-process Global Hash Yes Yes

Legend

VTL, NAS, or LFS
Is the target a virtual tape library (VTL), Network Attached Storage (NAS), or a locally attached filesystem (LFS)
Integrated or Standalone
If the VTL will copy its virtual tapes to physical tapes in a library connected behind it, the it is considered an :Integrated tape library. If you must use your backup software's traditional way for copying backups from one tape to another in order to copy data from virtual tape to physical tape, then it's a Standalone VTL.
Appliance, Gateway, or Software
An appliance is a complete system containing a head and all necessary disk. A gateway is a server head provided by the vendor that is ready to plug into disk of your choice. Software products do not provide any hardware, although they may specify certain system types that are certified with their software.
De-dupe
Does the product identify and eliminate redundant data
Inline
If the product does deduplication, is the redundant data identified and eliminated before it ever hits disk (i.e. inline, also known as in-band or synchronous), or does the product write the backup to disk, then have a separate process read and deduplicate it (post-process)?
Dedupe Domain
The bigger the amount of data that is compared against each other, the better the deduplication ratio, especially in a multi-appliance environment. Many deduplication appliances dedupe data only against other data stored within a single filesystem or in the storage connected behind a single head (i.e. local dedupe.) Some dedupe appliances can accept data from multiple heads and still de-dupe all data against all other data, regardless of which head it comes into (i.e. global dedupe).
Dedupe method
One of the methods for identifying redundant data is the creation of a SHA-1 or MD5 hash. If two blocks of data have the same hash, they are deemed identical. For a heated debate on the merits of the "hash collision" issue, check out this thread in the NetBackup forum. Another method is delta differencing, where tonight's backups are simply lined up against last night's backups and compared bit-for-bit. This is a very old technique - the difficulty now is in using this methodology against backups from various sources. (Traditional delta differencing systems did so within the backup software.)
Open-Storage API
To say YES in this column, the vendor must support Symantec's Open-Storage API, which is designed to control intelligent disk target devices from NetBackup.