Mirroring vs Raid

Digerati said:

Raid vs Mirror.

Mirror is a RAID type, RAID1 specifically.

Can I have more than one mirrors?

Still don't know what you mean by that. As I said, you can have as many as you have spare disks.

If you mean can you have 4 drives running at once, all mirrors of each other, then no, not on the same computer. You can have a mirror on one computer, then have a mirrored computer elsewhere on network, or across the planet.

In "Simple terms" RAID essentially makes a bunch of disks appear as "a unit" so a failure of any one of the disks within the array *can* and probably will lead to data loss.

No, that is not true. With a striped array, RAID0 for example, then the data is spread across multiple drives, so then if one drive fails, you have lost data. But the whole point of mirrored arrays is precisely for when one of the disks in the array fails, and in that event, there will be NO data loss. Saying it *can* is a bit of a cop out - you *can* win the lottery tomorrow too. But saying it probably will lead to data loss is simply wrong for any mirrored array, and there are several types, not just RAID1, that support Mirroring.

Mirror is an ability that comes with windows 7. When I say mirror I mean the feature you can commit under Disk Management. AKA Mirror HD in Disk Management has a screen capture.

The idea here behind my post was never backup. I was considering the amount of pain and suffering I'd have to undertake with motherboard based hardware raid should my motherboard die or should I decide to upgrade. At such even the only place I may be able to access my data is on the external drive.

I was asking the pros and cons of "software raid" or "mirroring" (as windows likes to call it) versus motherboard based hardware raid.

Okay, now I see what you are saying about Win7 mirroring. Interestingly - oddly - there is little information on Win7's Mirror feature. But I found some. This is, obviously, a software based RAID. Software based RAIDs work, but as you can guess, all of the processing is done in system memory, using CPU cycles. Therefore, it will result in a performance hit. Using this method, I think you can add mirrors.

Here is some information: Information regarding Windows 7 software Raid : Alan's World Famous Blog V2

Digerati said:

Okay, now I see what you are saying about Win7 mirroring. Interestingly - oddly - there is little information on Win7's Mirror feature. But I found some. This is, obviously, a software based RAID. Software based RAIDs work, but as you can guess, all of the processing is done in system memory, using CPU cycles. Therefore, it will result in a performance hit. Using this method, I think you can add mirrors.

Here is some information: Information regarding Windows 7 software Raid : Alan's World Famous Blog V2

Right. So...

What would happen if the main disk dies in win7 mirroring?
Would I be able to make a "mirror" my main disk?
Should I switch to win7 mirroring?

What would happen if the main disk dies in Windows 7 mirroring?

IN THEORY - if the main disk fails, you ensure the mirrored spare is in the boot position and press on.

Would I be able to make a "mirror" my main disk?

That's the idea.

Should I switch to Windows 7 mirroring?

From what? And why?

We really don't have a clue here what you are doing or why you need to use RAID. The best solution for performance, IF YOU NEED RAID is to use a good add-in RAID controller card - and it would not be Mirrored either. The next best is to use the RAID controller on the motherboard. Then finally a software based RAID.

The best solution to ensure data integrity is a good backup program. RAID is never a suitable substitute for a backup program.

So tells us what your goal is, then maybe we can give you better opinions specific to your needs, rather than a bunch of generalities.

Digerati said:

What would happen if the main disk dies in Windows 7 mirroring?

IN THEORY - if the main disk fails, you ensure the mirrored spare is in the boot position and press on.

Would I be able to make a "mirror" my main disk?

That's the idea.

Should I switch to Windows 7 mirroring?

From what? And why?

We really don't have a clue here what you are doing or why you need to use RAID. The best solution for performance, IF YOU NEED RAID is to use a good add-in RAID controller card - and it would not be Mirrored either. The next best is to use the RAID controller on the motherboard. Then finally a software based RAID.

The best solution to ensure data integrity is a good backup program. RAID is never a suitable substitute for a backup program.

So tells us what your goal is, then maybe we can give you better opinions specific to your needs, rather than a bunch of generalities.

Okay. First off my main goal here is not performance. While I do not want to have any noticeable performance loss... I am not looking for raid 5... Just raid 1 (mirroring). I am kind of confused in weather to use software or hardware raid. Basically performance is not a priority.

My goal is to have a system that operates without fail and minimum down time. Now I do not operate a server but I need to be able to use my computer in full capacity even during the events of hardware failure. That failure very well can be mechanical failure of the rotating disks in the hard drives themselves or the motherboard dying on me. I cannot think of any other types of hardware failure I should be prepared for so feel free to indulge me with it.

While having weekly/monthly backups insures preventing data loss, the event of a drive failure would mean I'd have to spend time, valuable time, moving the data off of the external disk back into the replacement drive and also possibly reinstalling windows and all other applications that I regularly use. That can easily take two or more days. There are times when two hours is not the kind of time you want to waste let alone two or more days.

In the event of my motherboard dying (or upgrades) I also do not want to be seeking a "compatible" motherboard with my older raid. I merely want to avoid such a restriction stirring me away from better hardware options. This is like avoiding IDE like plague. An external card maybe a nice idea but I am not in the US and those cheaper ($100) cards are probably not available. So my options are $439.99 and up (Raid controller cards for 8 drives as they are listed on newegg.com). That was the cheaper US price by the way... That's a lot of money. Also during my recent drive failure I experienced several blue screens until I pulled the drive out since I had no way to disable the individual drive.

My motherboard already has raid support (raid 1,2 & 5) and I already setup my drives to use raid 1 through the use of the controler on my motherboard. Being the idiot I am I had taken action before asking adequate amount of questions.

I do not quite regret using motherboard-based hardware raid but I later learnt about the possibility of incompatibility between different raid controllers whom all seem to have their own way to handle raid. I can buy an exact make of my motherboard this year and the next but the one after there simply is no way to know.

While it is quite unlikely for a motherboard to die but in such event all my data and working drives would cost me a significant time to re-setup.

So I am kind of unsure weather to continue with hardware raid or migrate to software raid.

Everything I know so far suggests software raid to be better to avoid incompatibility issues and maintaining minimum downtime. But I honestly do not know how reliable software raid is or how much of an impact it would have in performance.

Just as a side note, it is not necessary to quote my whole reply each time - that really adds to the length, not to the "flow".

My goal is to have a system that operates without fail and minimum down time.

Well, that's what everyone wants.

I think we have already answered your questions, a couple times over.

The best solution is a card. This ensures you can take the entire raid (controller and drives) to a new platform, should something happen to your motherboard.

The best solution with a card is use the RAID for your data and applications only. That is, have a C drive with your operating system and hardware drivers. Then use the RAID as your D drive and install all your applications and save all your data to the D drive.

In this way, if your motherboard fries, you can buy any new motherboard, install the OS, then add your array. If you use RAID for your OS too, it may not boot if used with a different motherboard as all the hardware devices integrated on the board may be different, and require different drivers than those on the RAID.

Use 3 hard drives and keep the spare handy. Then if a drive fails, you just swap them in.

I am not in the US and those cheaper ($100) cards are probably not available.

Understand it is not likely these cards, cheap or expensive, are made in USA. Therefore, unless you are in some tiny 3rd world country, I suspect you can buy something reasonably priced. I note your profile time zone map includes the UK - Adaptec RAID PCI-E E-SATA PCI-E Card - £57.87 using external SATA drives.

HOWEVER, understand that if you have a viable backup system - perhaps regular images of your drive, and if your drive fails, you slap in a new drive, re-image the drive and move on. Admittedly, this can be a daunting task, but like any complicated task, becomes second nature with practice. But again, if the motherboard fails too - say you take a lightning strike and it takes out all your hardware (a primary reason to use an UPS, BTW) and you lose your drives too, the image file may have the wrong drivers too.

My point? There is no single solution to a robust backup program. I use RAID as my D drive. All my programs and data are on D drive. But I also regularly save all my data to a networked drive in another part of the house. So even if I have to build a new computer from scratch, I still have all my old data.

I don't currently live in a 3rd world country but in this place my options are a bit too limited. For instance when I was in the US and was enjoying 802.11B people here were forced to use 802.11G with its ridiculous price back then. It is not the lack of technology, its just over the top prices due to over the top hardware when you are looking for something much more basic. Also there is ridiculous taxation... I'll look around more throughly though.

I have been throughly informed on hard ware raid and the best course of action(s) concerning that. So...

At this point my main lack of information is how well windows 7's mirroring (software raid) works. That is... I want to know the pros and cons. I may do a combination of hardware raid and software raid. Software raid to an external e-sata drive may be a good form of backup.

If it all boils down to costs, I think you would do better to look into a good backup routine, and skip RAID altogether.

I have a limited amount of funds and want to make the best of it. Right now I am juggling 3TB of space and I want to make the best of it.

Can I simply have more info on windows seven mirroring please?

I already gave you what I can find. Sorry - there just does not seem to be much interest in a software based solution so not much is written on it - even at Microsoft.