Apple OS X File System Troubleshooting

Just FYI...here are three ways to troubleshoot or repair your Apple OS. Even though we all know we may never have to right?

File System Troubleshooting

We need a functional file system in order to run the operating system, and the software that drives the file system must be very reliable. Most file system failures are due to bad hardware or media. It doesn’t matter how fantastic the software is; if the hardware is no longer reading or writing, it’s pretty much useless to the file system. However while troubleshooting, you determine catastrophic hardware failure to be the problem, there really isn’t anything software can do to repair the device. Only a data recovery service, such as DriveSavers, might have a chance at recovering your data.

If you are experiencing file issues, but the hardware appears to be OK, you may have partial hardware failure or file system corruption.

1. Gather File System Information

Before attempting to fix the problem, one should have a complete understanding of the file system configuration. The /Applications/Utilities/Disk Utility application is the main tool for gathering system information. Availability and status of the storage hardware determines the function or non-function of the device.

• Opening Disk Utility scans the system for all devices and volumes.

• If a specific drive or volume is needed, simply select the item in the column on the left and click the info button in the toolbar.

• The most important determination if the device is working is the (Self-monitoring, Analysis, and Reporting Technology) or SMART status.

If the drive doesn’t appear in Disk Utility, chances are it has suffered from catastrophic failure.

• Double check the device status with Applications/Utilities/System Profiler.

• Opening System Profiler, the drive’s information should appear when you select the bus that the drive is connected to, such as Serial-ATA or FireWire.

One may have to remove the device from the computer and attempt to connect it to a totally functioning system.

2. Verify or Repair a Volume

Use Disk Utility to examine and attempt to repair a volume’s directory database which is used by the file system to catalog where files and folders exist on the drive. To access data on the drive, the file system must first check with the directory database in order to locate the appropriate bits on the drive that make up the requested file. Any damage to the volume’s directory database can lead to serious problems, including data loss. Before any volume is mounted, the Mac will automatically perform a quick consistency check to verify the volume’s directory database. The system will also quickly scan the startup volume during the boot process. However, if the system is unable to mount a volume, you are experiencing issues accessing a volume, or you are booting from the startup disk, you can use Disk Utility to verify and repair a volume’s directory database.

To use Disk Utility’s verify and repair features:

• If attempting to repair the system drive, first boot from the Mac OS X Install media and then choose Disk Utility from the Utilities menu.

• If you are on a currently running Mac, make sure the drive you wish to verify or repair is currently attached to the computer, then open /Applications/Utilities/Disk Utility.

• Select the drive or volume you wish to verify or repair from the column on the left, and then click the First Aid tab to the right.

• Verify the selected item by clicking the Verify Disk button in the bottom-right corner.

• It may take a few minutes to complete the verification process. During this time Disk Utility will show a progress indicator and log entries in the history area.

• Click the Show details checkbox to view more detail in the history log. You can stop the process at any time by clicking the Stop button.

• If no problems were found, you should see an entry in the history log with green text. If problems were uncovered, they will appear in bright red text.

• If the drive has problems, and you haven’t already started the repair process, you should do so now.

The system will continue to run the repair process until no more problems are found.

3. Using FireWire Target Disk Mode

The Mac hardware has a unique ability to share its internal drives via a feature called FireWire target disk mode. When FireWire target disk mode is engaged, the Mac will bridge any internal drives to the FireWire ports instead of booting normally from the system disk. Because target disk mode is a function built into the Mac’s hardware, you can still use this feature even if the installed operating system volume is corrupted. As an administrative user one can enable FireWire target disk mode on a currently running Mac:

• Click the Target Disk Mode button in the Startup Disk preferences. (Good system)

• Engage the target disk mode during system startup by holding down the T key while you turn on the Mac. (Corrupt system)

• Once target disk mode is engaged, you will see a large FireWire symbol on the screen, simply plug the targeted Mac into another fully functioning Mac via a FireWire cable.

• The targeted Mac’s internal volumes should mount normally on the other Mac as if you had plugged in a normal external FireWire-based drive.

At this point, you can do anything to the targeted Mac’s internal drive that you could do to any local drive, including installations, repairs, and data migration.

Note:

FireWire target disk mode is not supported on any Mac that lacks FireWire ports or uses third-party storage interfaces

Target disk mode cannot be engaged during system startup when using a Bluetooth wireless keyboard

I hope this article has been helpful. For more indepth information, this article was taken from:

White, Kevin. "Mac OS X Support Essentials: File Systems." Mac OS X Support Essentials: File Systems. 29 Oct. 2009. Web. 4 Oct. 2015.