5.2 Troubleshoot Drive and Raid Issues

What are the most common causes of storage device problems?

Bad adapters, a bad or failing drive, or improper connection

LED status indicators

LED indicator lights are typically visible on storage devices. A blinking light usually mean a busy drive, while a light that stays off or stays solid may be an indicator of a problem. Look at vendor specifications for indicator lights as they will vary between products.

Storage Failure Symptoms

Read/write failures “Cannot read from the source disk”. Slow performance, indicated by constant LED activity. Loud clicking noises, “the click of death”, may also include grinding and scraping

Grinding Noises fixes

Grinding, squealing, or scraping noise is a major indicator of imminent failure of the motor or spindle within an HDD. Can’t fix, back up the drive immediately and replace it.

Troubleshooting disk failures

Get a backup disk, check for loose or damaged cables, check for overheating, check power supply, and run hard drive diagnostics, preferably from a know-good computer.

Bootable Device Not Found

During bootup, a storage device is detected by the BIOS/UEFI first and then the OS. A “Bootable Device Not Found” error may indicate complete failure to boot. If the OS cannot be found, it can see the drive but not the OS on it. If BIOS fails, check boot sequence, then the cables between the motherboard and the drive. You can also check the drive in a different computer. If OS fails, may have a problem with the master boot record (MBR).

Data Loss/Corruption Fixes

Loss or corruption of data can be caused by a failing or full drive. First, remove extra files or applications, or defragment the drive. Next, you can format the drive and reinstall the OS. If still loss/corruption, the drive is failing and needs replaced. Repairs are difficult and expensive, it’s always better to have a backup instead.

RAID Failure Troubleshooting

If RAID failure, determine if problem comes from a single drive or the whole system. Check indicator lights and error messages, could be an issue with hardware, power, or communication. Each RAID has different drive requirements, so don’t pull drives until you’ve checked which one it is!

RAID Failure Conditions

RAID 0, Requires 2 or more disks, A single drive failure breaks the array with data loss

RAID 1, Requires 2 or more disks, Array works as long as one drive is working

RAID 5, Requires 3 or more disks, Need all drives operational but one

RAID 6, Requires 4 or more disks, Need all drives operational but two

RAID 10, 4 or more disks required, Can lose all but one from each set of mirrors

Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T) Failure

Software installed on drives that monitors hard drive reliability and performance. S.M.A.R.T. metrics can be useful, but are complicated and difficult to parse. You can use 3rd party software to view these statistics, look for warning signs, and schedule disk checks. Can create performance benchmarks that can help diagnose potential drive failures over time with automated notifications. Helps identify and replace the drive before it becomes a problem.

Extended Read/Write Times Troubleshooting

Extended read/write times can be indicators of a full or failing drive. First, backup files, remove extra files or applications, or defragment the drive. Next, you can format the drive and reinstall the OS. If still loss/corruption, the drive is failing and needs replaced.

Low Performance IOPS (Input/Output Operation Per Second)

IOPS are how many reads and writes a storage device can perform in a second. IOPS is listed as a metric on storage devices for performance comparison. A declining or low IOPS can be a sign of drive failure. For example, HDD may have 200 IOPS and SSD 1,000,000 IOPS

Missing Drives in OS Troubleshooting

Internal may have a bad drive or disconnected cable, external may have no power to drive or bad cable connection. Check connections, check the BIOS to ensure the drive isn’t disabled, find the drive in disk management or disk utility, ensure it is prepared and partitioned, update the drive drivers, and check for bad sectors, which may cause the OS to show the drive as unreadable. Network shared drives can be connected during startup, with option to reconnect at sign-in or connect with login script.

Missing Array

Multiple possible causes for missing or faulty RAID controller. Could be physical issue, like failed drive or loose connection. Could be problem with RAID controller, including misconfigurations in controller detection, incompatible controller driver, or a fault in the controller. Potentially due to data corruptions or misconfigurations of the RAID array.

RAID Audible Alarm

RAID arrays can produce an audible alarm if a problem is detected. Common causes include drive failure, power supply failures, or cache errors. May also trigger during drive rebuild due to failing or replaced array.