ZyXEL NAS540 User Guide - Page 65

Chapter 4 Web Configurator Basics Table 19 S.M.A.R.T Info LABEL Updated DESCRIPTION This indicates when the hard drive updates the value for this attribute. When Failed • Always means the hard drive updates this attribute during normal operation and during offline activities. • Offline means the hard drive only updates this attribute when no one is accessing the hard drive. This column indicates when (if ever) the attribute failed. An attribute has failed if the normalized value is less than or equal to the threshold. Raw Data Close • -: This displays if the attribute is not failing now and has never failed in the past. • FAILING_NOW: This displays if the attribute's current normalized value is less than or equal to the threshold. • In_the_past: This displays if the attribute's current normalized value is greater than the threshold but the worst recorded value is less than or equal to the threshold. This is the attribute's unprocessed raw data. These values show exact amounts of time or numbers of attempts or errors. The meaning to the raw values is specific to the hard drive manufacturer. Table 42 on page 156 has some information about whether a higher or lower individual raw S.M.A.R.T. attribute value is better. Click this button to close the screen. 4.4.6.1 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 20 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. NAS540 User's Guide 65