Volume Status - ZyXEL Communications NSA-2400 User Manual

• Choose RAID 5 if you need more disk space available for data and if up to one disk
failure is acceptable. RAID 5 uses 75% of the available space for your data. All data
can be recovered if one disk fails. If two disks fail then, all data in the volume is lost.
If one disk fails, the volume is degraded and will perform more slowly than a healthy
volume. You should shut down the NSA, replace the faulty disk and then
resynchronize the volume to attain previous performance.
• Choose RAID5_SPARE if you need the volume to recover as soon as possible in the
event of a disk failure. RAID5_SPARE operates as a RAID 5 with three disks while
the fourth disk is on standby. The standby disk automatically comes into play if a disk
in the 3-disk RAID5 volume fails. The advantage of RAID5_SPARE over RAID 5 is
that if a disk fails, then the volume resynchronizes automatically with the standby disk
and operates at healthy volume speed after the resynchronization. RAID5_SPARE
uses 50% of the available space for your data.
7.3.1.5 External Disks
You can configure JBOD or BACKUP on external USB disks. Choose BACKUP if you
intend to use the backup menus to copy data from the NSA internal drive(s) to an external
USB drive.

7.3.2 Volume Status

You (the administrator) can see the status of a volume in the Status, Storage > Overview or
Storage > Volume screens.
The NSA-2400 has the following classifications for the status of a volume:
• Healthy if all disks in the volume are OK and the file system is functioning properly.
• Resynching when you create or repair a RAID volume.
• Waiting Resync when there is already another volume resynchronizing. Only one
volume can resynchronize at one time.
• Degraded when a volume is currently down, but can be fixed. Data access may be slower
from a degraded volume, so it's recommended that you replace the faulty disk and repair
the volume as soon as you can.
• Down when a volume is down and can not be fixed.
A down RAID volume cannot be used until you repair or replace the faulty disk(s) in the
volume. Degraded means one of the disks in the RAID volume is not available but the volume
can still be used. For a degraded volume, you should replace the faulty disk as soon as possible
to obtain previous performance. See your Quick Start Guide for more information on replacing
a disk. If there is already another volume resynchronizing, then you will see Waiting Resync
as the volume status.
If it's down, then the only indication is that they can no longer transfer files to/from the shares
in the down volume. If it's degraded, then file transfer to/from the shares in the degraded
volume will be slower.
There is no explicit message from CIFS that tells users their volume is
degraded or down.
NSA-2400 User's Guide
Chapter 7 Storage Screens
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