Quantum 3.5.1 User Manual

Chapter 10  Managing Storage Disks

Storage Disk Deduplication

StorNext User’s Guide

240

• Use complete and physically dedicated file systems (snfs, local, nfs, 

or other,) for storage disk data, not shared file systems or file systems 

with linked directories.

• If your file system includes storage disks and you accidentally fill it 

with unrelated user data (i.e., non-storage disk data,) call the 

Quantum Technical Assistance Center and ask for a procedure to 

clean up and transcribe data.

Storage Disk Deduplication

StorNext supports storage disk deduplication only on non-managed file 

systems. Deduplication frees disk space by eliminating redundant data. 

The deduplication process does not retain duplicate data, so there is only 

one copy of the data to be stored. (Indexing of all data is retained in case 

that data is required later.) The main benefit of deduplication is that it 

reduces storage capacity requirements because only unique data is 

stored. Without deduplication, offline copies of a file consume as much 

disk space as the original file.
When you create a new storage disk, you will be given the option of 

enabling deduplication. StorNext refers to a storage disk with 

deduplication enabled as a dedup SDISK. If your system configuration 

consists only of storage disks, the same rules that apply to storage disks 

apply to deduplication-enabled storage disks. For example, in a storage 

disk-only configuration the first storage disk must always use file copy 1. 
You can create up to 4 dedup sdisks. (You can have a total of 16 storage 

disks, of which 4 can be dedup sdisks.) 
You must have a minimum of 2GB of RAM for each dedup sdisk you 

plan to use. 

At this time storage disk deduplication is supported only on 32 bit and 64 

bit Linux platforms. 

The 2GB of RAM per dedup sdisk is in addition to the memory 

required for StorNext.