User Manual
Klegg Electronics Inc.
20
www.klegg.com
Chapter 7 NDAS Bind Management
7.1 About NDAS Bind
Multiple NDAS devices can be used as if they are a single disk. This is called a NDAS bind and
it can be created and managed by
NDAS Bind Management
tool. You can bind multiple
NDAS devices for more capacity per volume, more performance or protection from hard disk
failures.
NDAS support three bind types:
Aggregation
,
Stripe(RAID0)
and
Mirror(RAID1)
.
A. Aggregation (also called spanned disk or JBOD)
- Allows any number of NDAS device units between 2 and 8 to be recognized as a single
disk drive.
- Useful when a larger storage device is needed.
- This bind does not provide any fault tolerance. If any one unit fails, all data is lost.
B. Stripe (also called RAID0)
- Allows 2, 4, or 8 NDAS device units to be recognized as a single disk drive.
- Useful when a larger storage device is needed.
- This bind does not provide any fault tolerance. If any one unit fails, all data is lost.
- Every read/write access is split into each disks. So if you have a proper network equipment
and network layout, you can get better performance.
Warning:
Because the block size of the striped disks is not 512 bytes, some applications or operating
systems may not access striped devices correctly.
C. Mirror (also called RAID1)
- Allows 2 NDAS device units to be mirrored. You can add one more NDAS unit device as a
spare disk.
- Provides fault tolerance. All data is written to both devices, so data can be accessed even
after one device fails.
Warning:
Mirroring(RAID1) protects data only from hard disk failure. It cannot protect data from logical
error such as file system error or incorrectly written data by application software. You need to
backup your data to another storage regularly to prevent these kinds of data loss.
