CompTIA A+ 220-1201 (5.2 - Troubleshooting Storage Devices)

Storage failure symptoms

• 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

Troubleshooting disk failures

• 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

Boot failure symptoms

• 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

Grinding noises

• Hard drives are mechanical devices

- Spinning drives (often 5,400 RPM and higher)

- Moving actuator arms

• Very high tolerances

- One small problem can cause the drive to fail

• Metal on metal

- Clicking or grinding

- Poor performance, or no access at all

• Difficult to recover from this issue

- Time to get your well-managed and

very recent backup

Troubleshooting disk failures 2

• Get a backup (if possible)

- 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

Boot failure symptoms 2

• 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

Troubleshooting boot failures

• 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

Data loss/corruption

• 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

RAID failure

• A drive in a RAID array has failed

- Hardware failure, power issue, communication issue

• Almost always very obvious

- Error messages

- Email notifications

- Audible alarms

• A careful analysis is required

- Many drives, different volumes

• Each RAID is different

- Don't start pulling drives until you check the console!

S.M.A.R.T.

• 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

S.M.A.R.T. analysis

• Monitoring S.M.A.R.T. metric over time

- Watch for changes or incrementing values

- May be part of a NAS or third-party software

• Automated notifications

- Email

- Text message

- Console notifications

• Resolve the issue before it's a problem

- Get a good backup

- Replace the bad drive

Extended read/write times

• 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

Missing drives in OS

• 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

RAID recovery