- [Instructor] One of the issues you might see is
RAID is not found.
Well, that's not good
if you're booting to the RAID array.
That means you can't boot to Windows,
or whatever operating system you're using.
So if the RAID array can't be found,
you're gonna wanna check a couple things.
First, you're gonna check the RAID array in the firmware.
And that firmware could be in your UEFI or BIOS
if your motherboard supports hardware-based RAID,
or it could be a separate RAID adapter,
like an Adaptec or a different card,
that runs the connections
and takes care of all the processing for that data.
So you wanna access that firmware
to see if the array is still functional.
Now, if it's in the motherboard,
well, you have to go into the motherboard BIOS or UEFI,
you know, press F2 or Delete to get into that BIOS.
If it's a RAID adapter,
you might have to press a separate key like Control + I,
or something,
to get into that.
And by the way, the RAID adapter card's firmware
usually boots before,
it usually shows up on the screen
before the motherboard of BIOS.
So keep that in mind
and you might not have much time to actually catch that.
But once you get into that firmware, wherever it's located,
you wanna see if that array is still functional.
So you wanna check those drives.
It might be that the RAID 1 mirror is broken,
and you have to replace one of the drives,
and then copy the data back over to reestablish the mirror.
It could be that the RAID 5 array has failed,
because one drive has failed for whatever reason.
And in that case, you'll have to replace that drive,
and then rebuild the array from the parity data,
or usually the better bet
is to restore the data from backup.
So here we'll show an example of a RAID array
or just a RAID adapter that cannot be found.
Here, I have one of my servers
and it can run RAID
but it's not right now.
So we have to troubleshoot that.
And so what I'm gonna do is go to Advanced,
go down to SATA Configuration,
and press Enter.
Now, you'll see this setting here, SATA Mode Selection.
The default is AHCI,
which is what you use
if you're just working with SATA drives
in their regular state with no RAID at all.
And so you can boot off for this drive,
and you can see other drives, and so on.
But if you want to use RAID
and actually be able to access the RAID adapter
and create RAID arrays,
then you have to press Enter and change it to RAID
that's for this particular motherboard.
So different BIOS programs, different UEFI BIOS programs
will have different settings
and different navigation to that setting.
This is just one example and it's just for SATA drives.
But you may say, well, what happened here?
Well, generally, you would set it to RAID
and you would set up the RAID array.
But let's say someone reset the BIOS to defaults,
or they flashed the BIOS with an update,
that might also set it to the default at AHCI.
That's a default setting here.
So then you just lose access to the RAID array.
So we'd actually have to turn this on
and save those settings in the BIOS.
Then we could access the RAID utility.
So we'll do that now.
We'll do F4 to save and exit.
Yes.
That's gonna restart that server.
And at some point,
we'll get the option to access the Intel storage utility
by pressing Control + I,
and sometimes that's just after the initial BIOS,
sometimes it's before the BIOS if you have a separate card.
It depends.
So we'll wait for that.
Here we go.
Control + I to enter the utility,
gotta get in fast.
And so here we are.
We're into the RAID utility.
Now you wouldn't even have that option to press Control + I
to get into the Intel Rapid Storage Technology Enterprise
RAID utility,
if it was set to AHCI,
you wouldn't have that ability at all.
So first, you have to set it to RAID.
Now, this is a double problem.
This is two problems for the price of one,
a double whammy.
Not only was this reset
and we couldn't even access RAID
or get to the RAID utility,
but we see there's a RAID 1 mirror here
that has been degraded.
That's a bad sign.
That means that we don't have a RAID 1 mirror anymore.
In fact, we only have one disk.
That's a member disK here.
and that's because I took out the other disk.
I took out the other drive.
It was indeed a RAID 1 mirror
with two one-terabyte Western Digital drives,
but I took that one out,
so now it shows it as degraded.
You might also see a message such as broken,
or what have you.
So this is where we'd go to reset that,
but now we'd say,
hey, it doesn't even see the other drive.
So we'd have to figure out what the reason is for that.
Maybe it got disconnected,
maybe the drive was removed,
maybe the SATA connectors just loose.
So we'd have to get that connected,
get that other drive in there,
and then reestablish the mirror,
and make sure that it is functional and established.
So that's where you'd go to make those modifications.
So, again, what we had here was we had a double error.
We had a double issue.
We had,
the system couldn't even see RAID
and couldn't even get into this RAID utility
because the BIOS had either been reset,
or changed, or set to defaults,
or there was a flash update,
and that RAID setting went back to its default,
which was AHCI.
Then the second problem,
once we get in here,
we see that the mirror has been degraded,
'cause one of the disks is missing.
This 120-gig drive, that's a non-RAID disk,
that was never part of the mirror.
But this one is
and the other disk is missing.
So you gotta figure out what the problem is with that.
So that's one example of some RAID troubleshooting
that you do on the hardware side.
So here we have another image of another system
where we have two Intel drives,
each 120 gig,
and you can see that it says non-RAID right now.
We're in the Intel RAID utility,
but there is no RAID volume.
None are defined right now.
So that's another thing you might see,
where for some reason the RAID volume is missing
and you'd see non-RAID disk,
so for both drives,
which are,
you know, they are identical drives
that look like they should be part of a RAID 1 mirror.
So that's something else.
And excuse the image here,
but this is a real image of a data mirror,
using the same type of utility, RAID 1,
750 gigs was used for this,
and the status is normal.
That's what you wanna see here.
And we see we have the two member disks here.
So two one-terabyte drives,
but we're only using 750 gig
of that one terabyte for this RAID 1 mirror,
and status is normal.
So that's an example.
Now this is all hardware-based stuff that I'm showing.
And that's the way to go.
Generally, you don't want to go with software-based RAID.
You want to go with something that is firmware-controlled
and outside of the operating system
that you're using like Windows or Linux.
So remember, the best way to run RAID is hardware-based.
And before we continue with some of the issues,
you definitely wanna remember your RAID levels,
especially RAID 1, mirroring,
where you have two drives
that are connected to one controller,
identical drives,
and the data is mirrored to both drives,
and then, also RAID 5,
striping with parity,
where the data is striped across,
and the parity information is striped across as well,
and RAID 10 which combines RAID 1 mirroring
with regular striping without parity.
And you might wanna remember MTBF,
mean time between failures.
And you wanna be able to define
how many failures per million,
or mean time between failures for your RAID arrays.
But definitely know your RAID levels.
That's a little review right there,
but let's get back into some of the issues
that you might see.
But you also wanna check the physical connections
of the drives
to the RAID card or to the motherboard,
make sure that everything is secure,
verify the data connection and the power connection,
'cause either could cause a RAID failure.
So if the RAID array cannot be found,
make sure that you check all the connections,
make sure that you check the array in the firmware.
And the other possibility is RAID just stops working.
And it might stop working
and you can't get into the operating system
if you're booting from a RAID array,
or it could be that you're storing data on the array
and it suddenly stops working as you're working in Windows.
So you're gonna wanna view the array of drives
in Disk Management
and see, first of all, if the array is working properly
if you're running it in Windows,
otherwise, it'll just show up as one volume letter
in Disk Management,
and you wanna see if that's healthy or not.
Then, take it further and access the firmware
and analyze each drive.
You might be able to save drives as well
and you might be able to do that
with the sfc command, or the chkdsk command,
or third party tools.
So you're gonna wanna try to save the drive, if possible.
But if not, you're gonna need to rebuild the array,
and most likely restore the data from your backup.
So a couple other things to check.
You wanna check if it was a single drive failure
or if the failure was multiple drives.
Because that can be very telling.
A single drive failure that happens,
hard drives will fail.
It's just a matter of time.
But if multiple drives failed at the same time,
it could be a configuration problem,
a connection problem, or a power issue.
So you want to identify first
whether it's a single drive failure
or multiple drive failure.
Then you wanna look into whether it's a controller failure,
maybe the RAID card failed,
maybe the firmware portion for the motherboard failed,
or maybe the motherboard needs an update,
maybe there was a short.
Check for a controller failure
and consider using duplexing,
two controllers in a RAID 1 mirroring environment.
You can check for power surges
and subsequent RAID failures.
Power surges might happen.
You wanna make sure that your system's connected
to a good surge suppressor,
or line conditioner, or UPS.
And you can also check for improper rebuilds of the array.
Another person, another technician
might have rebuilt the array incorrectly.
So watch out for that as well.
And then, finally, software issues.
Watch for configuration errors, viruses,
or unauthorized deletion of a array, and so on.
It could be a user error,
it could be a virus,
it could be malware configuration problem.
So check all these things.
Think of all these things
as you're working with these errors
of RAID not found and RAID stops working.
Those two things can eat up a lot of your time.
So there's a lot of stuff to look at for you
and help you troubleshoot a little bit.
And that's it for the sub-lesson.