ZyXEL NAS540 User Guide - Page 67

Technical Reference

Page 67 highlights

Chapter 4 Web Configurator Basics Table 20 S.M.A.R.T. Attributes (continued) ID ATTRIBUTE NAME BETTER DESCRIPTION 204 Soft ECC Correction Low This is the number of errors corrected by software ECC (Error Correction Code). 205 Thermal Asperity Low Rate (TAR) This is the number of thermal asperity errors. Thermal asperity is a read signal spike caused by sensor temperature rise due to touching the disk surface or contaminant particles. 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 Low Rate 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 Low Cycle Count 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 Low Amplification Count This is the number of attempts to compensate for variations in platter speed. 228 Power-Off Low Retract Cycle 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 Low Rate This is the number of errors in reading from the disk. 4.4.7 Technical Reference This section contains background on JBOD and the RAID levels used on the NAS. JBOD • Minimum number of disks: 1 NAS540 User's Guide 67

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Chapter 4 Web Configurator Basics
NAS540 User’s Guide
67
4.4.7
Technical Reference
This section contains background on JBOD and the RAID levels used on the NAS.
JBOD
Minimum number of disks: 1
204
Soft ECC
Correction
Low
This is the number of errors corrected by software ECC (Error Correction
Code).
205
Thermal Asperity
Rate (TAR)
Low
This is the number of thermal asperity errors. Thermal asperity is a read
signal spike caused by sensor temperature rise due to touching the disk
surface or contaminant particles.
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 20
S.M.A.R.T. Attributes
(continued)
ID
ATTRIBUTE
NAME
BETTER
DESCRIPTION