ZyXEL NSA325 User Guide - Page 272

Chapter 11 Package Management 11.15.1 S.M.A.R.T Attributes The following table describes some common S.M.A.R.T. attributes. If a higher or lower raw attribute value is better, it is indicated in the BETTER column. Since S.M.A.R.T. attributes and their definitions vary by manufacturer, refer to the hard drive manufacturer for details about the attributes your hard drive supports. Table 88 S.M.A.R.T. Attributes ID ATTRIBUTE NAME BETTER DESCRIPTION 01 Read Error Rate Low Shows the rate of hardware read errors. If this is not zero, there is a problem with the disk surface or the read/write heads. 02 Throughput Performance High This is the hard drive's general (overall) throughput performance. A decreasing value indicates a problem. 03 Spin-Up Time Low This is the average number of milliseconds the hard drive took for spindle spin up (from zero RPM to fully operational). 04 Start/Stop Count The total number of spindle start and stop cycles. 05 Reallocated Low Sectors Count Total number of reallocated sectors on the hard drive. When the hard drive detects a read/write/verification error, it marks the sector as "reallocated" and transfers the data to a specially reserved (spare) area. The process is also known as remapping with "reallocated" sectors known as remaps. The more sectors the hard drive has to reallocate, the slower read and write speeds become. 06 Read Channel Margin This is the margin of a channel when it reads data. 07 Seek Error Rate Low This is the rate of the magnetic heads' seek errors. A failure in the mechanical positioning system, such as servo damage or a thermal widening of the disk, results in seek errors. An increasing number of seek errors indicate the condition of the disk surface and the mechanical subsystem are worsening. 08 Seek Time Performance High This is an average performance indicator for the seek operations of the magnetic heads. Mechanical subsystem problems cause this value to decrease. 09 Power-On Hours Low (POH) This is how many hours the hard drive has been in a power-on state. The raw value lists the total number of hours (or minutes, or seconds depending on the manufacturer). 10 Spin Retry Count Low This is the total number of spin start retry attempts. This is the number of attempts to spin up to fully operational speed the hard drive has made when the first attempt did not succeed. An increase in this value is an indicator of hard disk mechanical subsystem problems. 11 Recalibration Retries High This is the number of times recalibration was requested when the first attempt did not succeed. A decrease in this value is an indicator of hard disk mechanical subsystem problems. 12 Device Power Cycle Count This is the number of times the hard drive has gone through a full power on and power off. 13 Soft Read Error Low Rate This is the number of uncorrected read errors the hard drive has reported. If this is not zero, back up your data. 190 Airflow Low Temperature This indicates the temperature of the airflow measured by a Western Digital hard drive. 190 Temperature Difference from 100 High This indicates the value of 100 - the temperature in degrees Celsius. Manufacturers can set a minimum threshold that corresponds to a maximum temperature. 191 G-sense error Low rate This is the number of mistakes caused by impact loads. 272 Media Server User's Guide