ZyXEL NSA-2400 Guia Do Utilizador
Chapter 7 Storage Screens
NSA-2400 User’s Guide
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Storage efficiency assumes all drives are of identical size.
Performance rankings are approximations.
7.3.1 Choosing A Storage Method For a Volume
The following is a guide to help you choose a storage method for the various number of disks
supported on the NSA-2400. See
supported on the NSA-2400. See
for theoretical background on JBOD
and the RAID levels used on the NSA-2400. Typical applications for each method are also
shown there.
shown there.
7.3.1.1 One Disk
If you only have one disk, you must use JBOD. All disk space is used for your data - none is
used for backup. If the disk fails, then you lose all the data on that volume (disk).
used for backup. If the disk fails, then you lose all the data on that volume (disk).
7.3.1.2 Two Disks:
You may choose JBOD, RAID 0 or RAID 1. With two disks you could create:
• up to two JBOD volumes
• one RAID 0 or RAID 1 volume
• Choose JBOD for flexibility and maximum usage of disk space for data. You can
either add an additional disk to your one-disk JBOD volume (and so don’t have to re-
create shares, access rights etc.) or create a different JBOD volume (and create new
shares, access rights etc.).
create shares, access rights etc.) or create a different JBOD volume (and create new
shares, access rights etc.).
• Choose RAID 0 if performance matters more than data security. RAID 0 has the
fastest read and write performance but if one disk fails you lose all your data on the
volume. It has fast performance as it can read and write to two disks simultaneously.
Performance may matter more than data security to gamers for example. This method
may also be acceptable for data that is already backed up somewhere else.
volume. It has fast performance as it can read and write to two disks simultaneously.
Performance may matter more than data security to gamers for example. This method
may also be acceptable for data that is already backed up somewhere else.
• Choose RAID 1 if data security is more important than performance. Since RAID 1
mirrors data onto a second disk, you can recover all data even if one disk fails, but the
performance is slower than RAID 0.
performance is slower than RAID 0.
7.3.1.3 Three Disks
Choose a combination of JBOD and/or RAID 0 or RAID 1 for the reasons already outlined.
With three disks you could create:
With three disks you could create:
• up to three JBOD volumes
• one JBOD volume and one RAID 0 or RAID 1 volume
Table 37 RAID Quick Comparison
RAID Level
0
1
5
10
Number of Disks
2,3,4
2
4
4
Capacity
S*N
S*N/2
S*(N-1)
S*N/2
Storage Efficiency
100%
50%
(N-1)/N
50%
Fault Tolerance
None
YYYY
YYY
YYYY
Availability
Y
YYYY
YYYY
YYYY
Read Performance
YYYY
YYY
YYYY
YYYY
Write Performance
YYYY
YYY
YY
YYY