5.3 Troubleshooting Storage Devices

Question 1

Storage failure symptoms

Answer 1

• Read/write failure
  – “Cannot read from the source disk”
• Slow performance
  – Constant LED activity - Retry…retry…retry
• Loud clicking noise
  – The click of death
  – May also include grinding and scraping

Question 2

Troubleshooting disk failures

Answer 2

• Get a backup - First thing - a bad drive is bad
• Check for loose or damaged cables
• Check for overheating
  – Especially if problems occur after startup
• Check power supply
  – Especially if new devices were added
• Run hard drive diagnostics
  – From the drive or computer manufacturer
  – Preferably on a known-good computer

Question 3

Boot failure symptoms

Answer 3

• Drive not recognized, Boot Device Not Found
  – Lights (or no lights)
  – Beeps
  – Error messages
• Operating system not found
  – The drive is there
  – Windows is not

Question 4

Troubleshooting boot failures

Answer 4

• Check your cables
  – Physical problem
• Check boot sequence in BIOS
  – Check for removable disks (especially USB)
  – Check for disabled storage interfaces
• For new installation, check hardware configuration
  – Data and power cables
  – Try different SATA interfaces
• Try the drive in a different computer

Question 5

Data loss/corruption

Answer 5

• Hard drives are mechanical devices
  – They will eventually fail
• Repairs are difficult and expensive
  – Dust-free environment
  – Not always successful
• An SSD may simply stop working
  – Sometimes can read but not write
• Data becomes unavailable or corrupted
  – Can be impossible to recover
• ALWAYS HAVE A BACKUP

Question 6

RAID not found

Answer 6

• Missing or faulty RAID controller

Question 7

RAID stops working

Answer 7

• Each RAID is different
  – Don’t start pulling drives until you check the console!

Question 8

S.M.A.R.T

Answer 8

• Self-Monitoring, Analysis, and Reporting Technology
  – Use third-party utilities
• Avoid hardware failure - Look for warning signs
• Schedule disk checks - Built-in to most drive arrays
• Warning signs - Replace a drive

Question 9

Extended read/write times

Answer 9

• A lot happens when reading or writing data
  – Memory access, communication across the bus,
  spinning drive access, writing or reading the data to
  the storage device, etc.
• Delays can occur anywhere along the way
  – Need a way to measure storage device access
• Input/output operations per second (IOPS)
  – A broad metric of maximum performance
• Useful for comparing storage devices
  – Hard drive: 200 IOPS
  – SSD: 1,000,000 IOPS

Question 10

Missing drives in OS

Answer 10

• OS boots normally
  – Other drives not shown - Check the BIOS
• Internal drives
  – Bad drive or disconnected cable
• External drives
  – No power to the drive or bad cable connection
• Network shares
  – Shared drives can be connected during startup
  – Option to reconnect at sign-in
  – Connected with login script

Question 11

RAID

Answer 11

RAID 0. 2 or more |A single drive failure breaks the array with data loss.
RAID 1. 2 or more| Array will work as long as one drive is operational.
RAID 5. 3 or more | Need all drives operational but one.
RAID 10 4 or more | Can lose all but one from each set of mirrors