| Hard disk testing |
S.M.A.R.T.This is a clever acronym for a useful technology. We may even not know, but there are many sensors inside a hard disk that we can check and monitor for the drive health. What does S.M.A.R.T. stands for? Self-Monitoring, Analysis and Reporting Technology.  S.M.A.R.T. won't help in this case. History1992 - IBM introduces an option on AS/400 SCSI-2 hard disk drives, it is just a single binary bit (0 means it is working, 1 means is going to fail).1995 - Compaq, Seagate, Quantum and Conner create Intellisafe, which measures different health parameters on a hard disk drive. The result is a new standard: S.M.A.R.T. Standard?Every company applies the standard in its own way.Some add their own attributes. Depending on the company, the values are stored in different measure units. For example, the values could be stored in minutes or in hours, luckily the software that checks S.M.A.R.T. parameters knows how to distinguish them. S.M.A.R.T. option in the computer BIOSIn order to access the BIOS, when booting the computer press DEL or F2.Somewhere under Advanced Options, it depends on the motherboard manufacturer, we will see an option: HDD S.M.A.R.T. Capability [Enabled or Disabled]  S.M.A.R.T. BIOS option. The internal disk sensors are always working,. If we choose Enabled and the motherboard detects that some values are wrong, a warning message will be displayed during the boot process saying that the hard drive is going to fail.  Warning message when disk is going to fail. We do recommend to enable HDD S.M.A.R.T. Capability option as well as the option High Temperature Warning on the CPU. Needless to say is that it doesn't matter if HDD S.M.A.R.T. Capability option is enabled or disabled in order to use the test and monitoring software. |
| Reading the S.M.A.R.T. values | ||||
|
smartmontools This is the software we are going to use to read the attributes and its values. It is open source. The first version: October 2002. Home page: http://smartmontools.sourceforge.net/ Windows version: Get it from the download page: http://sourceforge.net/projects/smartmontools/files/smartmontools/ Get the latest release smartmontools-X.XX-X.win32-setup.exe Executable files are: smartctl.exe and smartd.exe Linux version: The GNU/Linux package is: smartmontools, available for any distribution. To install in Fedora 14: yum install smartmontoolsTo run the main utility: smartctlsmartd is a service that monitors the hard disk parameter values. smartctl is used to see right now the parameters and its values, also to run a test. Supported hard disk types It works on IDE, SCSI, SATA, PATA, connected to the mainboard with its corresponding cable. A developer's version is working on RAID, USB adapters and NAS (GNU/Linux version has more supported devices). For testing **/with these devices, we will use -d parameter. The updated support list is: http://sourceforge.net/apps/trac/smartmontools/wiki/TocSupport#SupportedDevices Sample output smartctl.exe -a /dev/sda
In this information section, we see the disk manufacturer. The Device Model is a good value to search for more information on the World Wide Web. If we google this ID, we may get the manual and some pictures. The Serial Number of the drive is an information usually printed on the disk, so this tool will help us to physically identify the disk when we are working with some of them. The User Capacity is not real, that's because of the different cluster size used by operating systems: the MBR, the FAT, and so on. ATA Version and ATA Standard parameters indicate values related to the disk speed capability. Local Time indicates the computer time. SMART support is available mostly 90% of times, and not available on really old drives.
This section is not so interesting, it shows if the self-test is currently running and the time needed to complete it, among other settings.
This is the most interesting part, we can see all the attributes and its values. The most important values are:
VALUE indicates the current value of the attribute. WORST is the worst value in its lifetime. THRESH is the threshold limit of the attribute, range from 0 to 255. If VALUE is less than or equal to the threshold, then the attribute has failed, which means that data on this disk is in danger. RAW_VALUE is the value as it is written on the disk, each vendor have its own algorithm to convert RAW_VALUE to VALUE.
Last section is a resume of the self-test. To perform a self test right now, you can use the computer meanwhile: The fast one, maybe two minutes: The slowest sector by sector check: smartctl -t long /dev/sdaWait two or three minutes for the short test and type: smartctl -a /dev/sdaTo see the results, you have to wait far more time when doing the long test. Recomendations:Power On Hours, POH, is a very important attribute (number 9). Vendors usually say that more than 5 years is enough time for a consumer hard disk. In five years, using eight hours every day the computer gives 14600 POH, that's a key attribute to check. Temperature (number 194) is the live temperature in Celsius. More than 60 ºC (140 Fahrenheit) is dangerous in most cases. Keep the hard disk cool always. Other related links about hard disksHere you can hear sounds of damaged hard disks: http://datacent.com/hard_drive_sounds.php Graphical user interface for smartmontools: http://gsmartcontrol.berlios.de Freeware Windows software HD Tune: http://www.hdtune.com/ Seagate Tools for Hard Disk Diagnostic: http://www.seagate.com/www/en-us/support/downloads/seatools For a complete hard disk erase DBAN (Darik's Boot And Nuke) http://www.dban.org/ | ||||