How does Windows handle a RAID 1 disk failure?

[kylef]

I have just thrown together a Raid 1 array for some friends who have had 2 hard disks fail on them in the past year and don't want to lose any data this way again. I'm using a Hightpoint raid controller that is integrated onto a Shuttle motherboard.

My question is this: should one of the two drives fail or develop errors, what happens? Presumably some type of GUI message would pop up, telling them that one of their drives has encountered errors, or has failed and needs to be replaced.

Highpoint distributs a "configuration" utility that can be run in the background. Does this NEED to be run in order for Raid 1 events to be logged? Or will Windows also handle such error reporting somehow?

I just don't want to get into a situation where they have this Raid 1 array, but a drive goes out and they are unaware because they don't check Event Log at all.

I want to know if anyone has had a Raid 1 disk failure in Windows and knows what happens.

Thanks for any help!

 

[boomerang]

If a drive fails, there will be a message at boot-up stating this. The boot process will halt. They will be able to continue and boot and run normally.

Whether they ignore this message at every boot and continue on merrrily for days or weeks is anyone's guess.

I've never had a failure but purposely induced one by disconnecting a drive. I too, wanted to know what would happen ahead of time.

 

[kylef]

Thanks for the response.

So that is what happens when a drive fails at boot time... but what happens if a run-time crash occurs, or if a data mismatch between the two drives occurs? Does something get triggered while Windows is already running?

Just curious...

 

[NogginBoink]

It sounds like you're using hardware RAID.

In that case, Windows is entirely unaware that you're using RAID, and what happens is totally dependent on the hardware.

 

[bsobel]

Highpoint distributs a "configuration" utility that can be run in the background. Does this NEED to be run in order for Raid 1 events to be logged? Or will Windows also handle such error reporting somehow?

As boomerang said, since your doing this in hardware Windows simply doesn't know about it. The HP app will monitor the drives and should alert you if there is a problem (so I guess in short, yes you need it). I run a couple 3ware boards on my server, that software will generate email upon any problems (nice but scary to get one of those 'drive 1 failed', 'hotspare enabled', 'array rebuilt' message). Not sure what alerting the HP app does other than onscreen notificaitons.

Bill

 

[kylef]

Thank you everyone for the responses. I think that technically the Highpoint controller is considered a "software RAID" solution, but I doubt there is much of a difference between it and the true hardware controllers when it comes to Raid-1 (just send the same command to two drives, right?). Raid-5 needs the hardware XOR support, but Raid-1 is pretty simple from a processing standpoint.

But it is certainly confusing to figure out what happens in the event of a failure. The documentation states only the following:
"The card's BIOS will display error messages during bootup. The RAID Management software will display warning messages, and any errors in it's event log."

It doesn't specify what types of errors it will log, and what kinds of failures are detected at runtime vs. boot time. But since these people leave the computer on 24/7, boot error messages are not really a good option. Therefore, it sounds like I should configure the raid utility to launch automatically at startup. Hopefully it won't confuse them too much to see it in their system tray

And just FYI, Raid-5 would have been my first choice, but it wasn't an option at this level (they only had an extra $100 to throw at the problem).

Thanks all!

 

[bsobel]

I think that technically the Highpoint controller is considered a "software RAID" solution, but I doubt there is much of a difference between it and the true hardware controllers when it comes to Raid-1 (just send the same command to two drives, right?). Raid-5 needs the hardware XOR support, but Raid-1 is pretty simple from a processing standpoint.

It's absolutely a hardware raid solution, not software. Software implies that the host OS is aware of and is participating in the raid activity. Such as if you setup a raid array via windows drive management.

It doesn't specify what types of errors it will log, and what kinds of failures are detected at runtime vs. boot time. But since these people leave the computer on 24/7, boot error messages are not really a good option. Therefore, it sounds like I should configure the raid utility to launch automatically at startup. Hopefully it won't confuse them too much to see it in their system tray

Didn't notice which OS you said, but if it's XP you can configure it to never show that icon in the tray (unless they hit the chevron to open the tray more)

Bill

 

[Nothinman]

Software implies that the host OS is aware of and is participating in the raid activity. Such as if you setup a raid array via windows drive management.

Not necessarily. Software implies that the RAID isn't being done on a dedicated CPU on the RAID card, it could be a software driver that handles the RAID but the above layers of the OS only see a single block device because that's what the driver presents it as.

 

[bsobel]

Not necessarily. Software implies that the RAID isn't being done on a dedicated CPU on the RAID card, it could be a software driver that handles the RAID but the above layers of the OS only see a single block device because that's what the driver presents it as.

No, that wouldn't allow the OS to boot (as it couldn't find the drivers needed since it wouldn't know how to access the disk device).... If the device is seen at the OS as a single device, it's gotta be hardware raid.

Bill

 

[Nothinman]

No, that wouldn't allow the OS to boot (as it couldn't find the drivers needed since it wouldn't know how to access the disk device).... If the device is seen at the OS as a single device, it's gotta be hardware raid.

So I guess you consider all those IDE RAID controllers hardware then?

 

[bsobel]

So I guess you consider all those IDE RAID controllers hardware then?

Absolutely, wouldn't you?
Bill

 

[Nothinman]

Absolutely, wouldn't you?

No. There's a little BIOS/firmware to make it bootable via INT13 routines, but the main part of the RAID is done in software. Look at drivers/ide/raid/* in the Linux kernel, if it was all hardware most of that code wouldn't be necessary. Particularly in the *_make_request functions, if it was hardware RAID the driver wouldn't have to decide which disk to submit a read request to.