1. Introduction To Computers
Troubleshooting Storage

2. Preventative Maintenance
All hard drives will eventually fail from use
Hard disk drives will eventually wear out due to their mechanical parts eventually failing
Solid state drives have a limited amount of times they can be read from and written to
Hard drives are sealed units to prevent contaminants and other damage to the platters
This means that if something mechanical goes wrong, then the drive needs to be replaced entirely instead of repaired
Because of this, one of the most important things we can do is run preventative maintenance by storing backups of our data to recover from

3. Slow Performance - Hardware Issues
One of the most common issues you’ll deal with is complaints about slow drives
First of all, a hard drive that has been running for a long time will run less efficiently than a newer one
One of the primary factors affecting hard disk drive speed will be its RPM. Anything less than 7200 RPM will typically feel slow
Disk interface will be your next physical bottleneck after rotational speed. PATA will be the slowest, followed by SATA, SATA 2, and finally SATA 3

4. Slow Performance - SoftWare / Files
A hard drive that is close to full will run poorly. Anything under 20% empty space is going to affect performance. If there isn’t enough free space, then consider deleting unnecessary files or upgrading to a new larger drive
If a hard disk drive is heavily fragmented, it will run considerably slower than a drive that has its data properly sorted
We can prevent this by running defrag tools regularly
Note that defragment tools need space to function, so if there isn’t enough free space the defrag tools will only be able to partially defrag the data

5. Boot Failures - Boot Sequence
If the computer says that it can’t boot into an operating system, this could be a huge problem or it could be easily solved
To figure this out, we’d have to first go into our BIOS settings to check boot order to see what devices we boot from
If we boot from USB or CD before our normal boot device then we have to make sure that there is no media there interrupting the boot sequence
If the boot device is after another hard drive we have to reorder our boot devices to boot from the operating system drive first
If the boot sequence is correct then check to see that the drive is recognized by the BIOS

6. Boot Failures - More serious
The MBR is the first sector of your hard drive that tells the BIOS where to look for the operating system on the disk
If your MBR (Master Boot Record) is corrupt or missing, then the operating system won’t be able to load
On Windows, you have to boot from the installation disc to enter the recovery environment
From here you have a few options
Automatic Recovery to have the system try to repair the MBR itself
/fixmbr: Repairs the master boot record
/fixboot: Repairs the boot sector
/rebuildbcd: Rebuilds the boot configuration data

7. Drive Not Recognized by BIOS
Modern BIOS automatically detects drives and their geometry during POST. In older systems, you had to manually enter the disk geometry, and it was very common for a wrong value to be entered or a jumper to be put into the wrong position causing an error
In a modern system, the most common cause for this error would be one of the following:
The power connector is unplugged or nonfunctioning
The SATA cable is unplugged or nonfunctioning
The drive is malfunctioning or nonfunctioning

8. Drive Error - Odd Noise
When a hard drive starts making abnormal sounds like clicking, grinding or whining, it’s a sign that the drive is dying
Since the hard drive is a sealed unit, there is not much in the way of physical repair we can do
The best thing to do would be to backup the data and stop relying on this drive. It is only a short matter of time before the drive fails

9. RAID Issues
If your workstation has a RAID setup, then you may need to troubleshoot the RAID
The most common issue requiring troubleshooting will be that the RAID isn’t found by the operating system
If we are using hardware RAID, then the most likely culprit is the RAID controller. Try updating its driver or replacing the part. If we need to replace the controller, we may need to restore the RAID from backup
If we are using software RAID, then the problem is more serious
Software RAID is created and controlled by the operating system which means if it isn’t working, there is a serious issue with the operating system or the storage devices

10. RAID Drive Failure
When we have drives configured into an array, we have the potential for hard drive failure. How serious an issue this is will depend on how the RAID is configured
RAID 0 - This will lead to full catastrophic data loss, since a small sliver of every file is stored on every device for performance increasing purposes
RAID 1/5/10 - These configurations are much more resilient to drive loss. If we lose a drive (or multiple depending on the configuration) all we typically have to do is replace the drive and wait for mirroring or parity to restore the data

11. SSD Fragmentation
Since there is no platter, and no read/write head to move, fragmentation is a much smaller problem on SSD drives than it is on HDD drives
However, defragmentation tools can actually cause issues for SSD drives by shortening their lifetime by moving files around
Every time data is written to a cell, that cell gets closer to failure. No matter whether that is new data or data being moved to fix fragmentation
This means that we should disable automatic defragmentation for any installed solid state drives from control panel - security and maintenance

12. SSD Lifetime
While performance is greatly increased in SSD, it does come at the cost of a much lower mean time before failure, which is the lifetime for the drive
Also, since the cells have a limited lifetime, we have to be wary of applications that overuse the storage with a lot of write operations. For example, image editing programs that create a lot of temporary backup files will shorten the lifespan of the drive needlessly
The issue is that these programs that degrade the SSD needlessly also typically benefit greatly from its increased read/write speed. If you feel you need to put these programs on an SSD drive, make sure to backup the data onto an HDD

13. TRIM
TRIM functionality helps to make SSD drives more efficient and reduce write/erase operations
TRIM will identify data blocks that can be erased, letting your SSD know to overwrite them
This is important because otherwise if an SSD needed to overwrite part of a block, it would store the block in cache, modifies the block in cache, erases what’s on the block, and then writes the new modified block
This is much slower, and adds write operations, compared to just overwriting a block entirely
TRIM should be enabled automatically, however, the command fsutil behavior query DisableDeleteNotify will let you know. 0 indicates enabled, 1 indicates disabled