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Chapter 7 Storage
NSA320 User’s Guide
172
figure shows two disks in a single RAID 1 volume with mirrored data. Data is
duplicated across two disks, so if one disk fails, there is still a copy of the data.
As RAID 1 uses mirroring and duplexing, a RAID 1 volume needs an even number
of disks (two or four for the NSA).
RAID 1 capacity is limited to the size of the smallest disk in the RAID array. For
example, if you have two disks of sizes 150 GB and 200 GB respectively in one
RAID 1 volume, then the maximum capacity is 150 GB and the remaining space
(50 GB) is unused.
Typical applications for RAID 1 are those requiring high fault tolerance without
need of large amounts of storage capacity or top performance, for example,
accounting and financial data, small database systems, and enterprise servers.
RAID and Data Protection
If a hard disk fails and you’re using a RAID 1 volume, then your data will still be
available (but at degraded speeds until you replace the hard disk that failed and
resynchronize the volume). However, RAID cannot protect against file corruption,
virus attacks, files incorrectly deleted or modified, or the NSA malfunctioning.
Here are some suggestions for helping to protect your data.
• Place the NSA behind a hardware-based firewall. It should have stateful packet
inspection, IDP (Intrusion Detection and Prevention), and anti-virus (like
ZyXEL’s ZyWALL UTM products for example).
• Use anti-virus software on your computer to scan files from others before saving
the files on the NSA.
• Keep another copy of important files (preferably in another location).
Table 28 RAID 1
A1 A1
A2 A2
A3 A3
A4 A4
DISK 1 DISK 2