ZyXEL Communications NSA210 - Manual (Page 156)

Chapter 7 Storage
NSA210 User’s Guide
156
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 it’s down, then the only indication is that you can no longer transfer files to/
from the shares in the down volume.
Note: There is no explicit message from CIFS that tells users their volume is
degraded or down.
7.5.4 Volumes and RAID
Note: Back up your data before deleting or re-creating a volume!
If you originally have one disk configured as JBOD, and you then install another
disk and want to configure the two disks to use RAID 1, you should first back up
all your data on the two disks (see the Memeo Autobackup utility on the included
CD) and then restore your data later after you create the new volume type.
Below is a table that summarizes some attributes of RAID 1 as supported on the
NSA. For capacity and storage efficiency, “S” is the size of the smallest drive in the
array, and “N” is the number of drives in the array.
Performance rankings are approximations.
7.5.5 Disk Replacement Restrictions
Note: If you’re using RAID 1 and the hard disk inside the NSA fails but the eSATA
hard disk is still working, you can remove the hard disk inside the NSA and
install the eSATA hard disk inside the NSA. Your NSA runs normally again, but
you will need to have another eSATA hard disk attached to the NSA in order to
employ RAID 1.
Table 24 RAID 1 Quick Overview
RAID Level 1
Number of Disks 2
Capacity S*N/2
Storage
Efficiency 50%
Fault Tolerance YYYY
Availability YYYY
Read
Performance YYY
Write
Performance YYY