Chapter 5 Storage Manager
NAS Series User’s Guide
80
5.4 iSCSI
The NAS supports the iSCSI (Internet Small Computer System Interface) standard and can serve as an
iSCSI target. When the iSCSI initiator is successfully connected to an iSCSI target over an IP network, data
transmission and storage management can be processed through the network. In other words, you can
access and manage the target the same way as a locally attached drive.
In the following example, a branch office has a NAS named NAS1. You want to expand your data
storage capacity by accessing an iSCSI LUN (Logical Unit Number) volume called VOL1 on NAS1 over
the Internet. Your computer is the iSCSI initiator and the NAS is the iSCSI target. When the initiator is
successfully connected to the target, your computer can use VOL1 on the NAS as its own internal
storage.
206 Flying Height This is the height of the hard drive’s read/write heads above the disk surface.
207 Spin High Current This is the quantity of high current used to spin up the drive.
208 Spin Buzz This is the number of buzz routines to spin up the drive. When the arm holding
the read/write heads is stuck, the motor driving it tries to oscillate the arm to
free it. This causes an audible vibration.
209 Offline Seek
Performance
This is the hard drive’s seek performance during offline operations. Offline
operations are tests the drive does itself as opposed to those that an external
diagnostic tool has it do. Seek performance is how quickly the drive moves
from track to track.
220 Disk Shift Low This is how far the disk has moved relative to the spindle (this kind of shift is
usually due to shock).
221 G-Sense Error
Rate
Low This is the number of errors that have resulted from external vibration and
shock.
222 Loaded Hours This is how long the hard drive has operated under data load (this requires
movement of the magnetic head armature).
223 Load/Unload
Retry Count
This is how many time the magnetic head has changed position.
224 Load Friction Low This is resistance caused by friction in mechanical parts during operation.
225 Load/Unload
Cycle Count
Low This is the total number of load cycles.
226 Load 'In'-time This is the total time that the magnetic heads actuator has had a load (not
been in the parking area).
227 Torque
Amplification
Count
Low This is the number of attempts to compensate for variations in platter speed.
228 Power-Off Retract
Cycle
Low This is how many times the magnetic armature was automatically retracted
because the power was cut.
230 GMR Head
Amplitude
This is the amplitude of thrashing (or the distance of repetitive forward and
reverse head motion).
231 Temperature Low This is the hard drive’s temperature.
240 Head Flying Hours This is the total time that the head has been positioning.
250 Read Error Retry
Rate
Low This is the number of errors in reading from the disk.
Table 36 S.M.A.R.T. Attributes (continued)
ID
ATTRIBUTE
NAME
BETTER DESCRIPTION
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