If you're having problems with a hard drive,
you might see different types of error messages occur.
If you see a message that says "Cannot read from the source
disk," then this drive may be having a problem reading
or writing information to that drive.
Or you may find that the overall performance to the drive
is very slow.
You might have slowness when reading or writing
to the drive, and you might see constant LED lights that
are flashing on that hard drive as you're
trying to read and write information to the drive.
When that's occurring, you might also hear a clicking noise.
This is sometimes called "the click of death,"
as the drive is trying to read access
information on that drive.
All of these issues are significant because they
show that you may be losing access
to the data that is on this particular storage device.
If any of this is happening, then the first thing
you should do is to get a backup of all of that data.
If this drive does happen to fail,
you want to be sure that you at least have a copy of all
of your important information.
Then you want to look for any loose cables or any damaged
cables that might be inside of your computer.
Maybe the problem is simply the cable connection and nothing
related to the overall operation of the drive.
Also check to make sure there's no overheating
inside of your system, especially
if these drive problems tend to manifest themselves
after your computer has been running for a while.
You also want to check your power supply
and make sure that your storage device is
able to get enough voltage.
This can be especially important if you
happen to have installed new hardware
inside of your computer, and you might
have a power supply that's not able to power
all of those devices at the same time.
And at the very least, you should run some hard drive
diagnostics.
Most manufacturers of hard drives
will provide you with diagnostic software that's
specific to that drive, and you want
to run that test from a known-good computer.
Sometimes the problems you're having
with your hard drive are occurring during the boot
process.
You might see lights or activity on the drive,
or there may be no lights that are
showing for hard drive access.
There might be beeping messages that
occur during the power on self-test,
or there might be error messages on the screen related
to your storage device.
You might also see messages related to the operating
system.
For example, "Operating system not found," which
means the hard drive is there, but there's no operating system
found on that hard drive.
One of the first checks that you can perform when you're
having these types of boot failures
is the connection to the drive itself.
You may want to disconnect and reconnect those particular data
cables and power cables going to the drive.
Also check the boot sequence in your BIOS.
You may find that you're trying to boot from a device that
doesn't have an operating system,
and you're not booting from the hard drive.
You can change the boot order inside
of your BIOS to choose one device over another.
You might also want to see if there are any removable disks
or USB-connected disks on your computer,
and that the BIOS isn't choosing one of those disks
before booting from the internal hard drive on your computer.
And of course, it's certainly possible
that storage interfaces are disabled in your BIOS.
So if you've connected a new hard drive,
you want to make sure your BIOS is able to see that drive.
If this is a brand new hard drive installation,
you may want to check the cables or replace the cables
for your data and the power.
You might also want to try a different set of interfaces
to make sure your problem isn't associated
with the interface on the motherboard.
And lastly, you may want to remove the drive completely
from your computer and try it in a different PC
to if the problem may be isolated to your system.
If you're in a server environment,
there may be multiple drives inside of your computer running
in a RAID array.
That's a redundant array of inexpensive disks
or a redundant array of independent disks,
depending on which definition you like to use.
You might see messages appear on the screen that
might identify a problem.
This one is showing that the integrated RAID
exception was detected.
A volume on that RAID array is in an inactive or optimal
state.
And it gives you an option to enter the configuration utility
to get more information about that error message.
When you start working with RAID arrays,
that means that you're going to have multiple drives that you
could pull from.
Some of these RAID arrays are very, very large.
This is a RAID array of 12 different disks.
Some are on one volume, some are on a different volume.
You need to always check exactly what drive is in your system,
and which one happens to be having a problem before you
start pulling drives out of that RAID array.
The RAID Management software will usually tell you exactly
which drive is having a problem and which
one should be replaced.
Once you replace the drive, you may
have to restore the data from a known-good backup
or the RAID array may be able to restore itself.
That will depend on which type of RAID is being used.
For example, for RAID 0, a single drive failure
will break the entire array and you will have data loss.
So if you replace a RAID 0 drive,
you'll need to restore from tape.
The other RAID formats--
RAID 1, RAID 5, and RAID 10, which is sometimes
called RAID 1 plus 0--
will all be operational if you lose a single drive.
And if you replace that drive, the RAID array
will recognize that it's a new drive,
and it will begin rebuilding the data on that drive
without having to restore from backup.
An error that can sometimes indicate a problem
with a hard drive is a Windows Stop error,
which is the blue screen of death,
or the Apple spinning wait cursor.
If these errors indicate that there is a storage device
problem, then we want to be sure we have a good backup
and perform some hard drive diagnostics on those storage
devices.
Many drives will tell you when problems
start to occur using a technology called SMART.
SMART stands for Self-Monitoring, Analysis,
and Reporting Technology.
These SMART metrics are being calculated inside
of every single drive that you have,
and you can see there are a number of different attributes
that are being gathered.
There are a number of different third-party utilities
and utilities that are built into operating systems that
allow you to get more information
about these SMART errors.
And you might be able to see spikes or changes
in the operation of your hard drive,
and be able to replace it before you lose any data.
If these drives are in a drive array,
there are usually scheduled disk checks that occur every month,
and there's constant monitoring of these smart statistics.
This allows the system administrator
to get proactive information of when a drive may be going bad,
so they can schedule a time to get the drive replaced
and make sure that everything continues to run
without any user downtime.