Mirror is useless if first drive fails

[thardie]

So, I installed windows 7 ultimate with 2 drives. I'm running on a MB with an AHCI (ICH10R SATA controller - No extra drivers needed. Win7 sees the drives fine during install). It did the normal thing on 1 drive of making a system reserved partition with all the bootmgr and BCD stuff. I'm not able to mirror it. But, I was able to mirror the main installation partition.

Forward a few days - Drive 1 (the one with the "System" (BCD and bootmgr) and the main installlation) dies. Now I have another drive with just the main installation. Of course, I can't boot anymore.

OK, I think - I'll add the missing boot files to the still working drive. I boot the install CD, go into a CMD prompt. Break the mirror, and make the working partition standalone. I copy bootmgr onto the drive's root, create a "Boot" folder. A run diskpart and mark the partition as active. I run bootrec/rebuildbcd (which works and finds my installation), bootrec/fixmbr (also works) and bootrec/fixboot (also works). Great, so now I can boot?

Wrong. I just get a blinking cursor on trying to boot. I've run through the GUI repair, and still no go. I cannot figure out what's missing.

So, the bottom line is - If you're using a mirror thinking you're safe - Think again. Your data will be safe, but forget ever booting that installation again (

 

[pbcopter]

In order to actually have a mirror you must set the BIOS to RAID and create a RAID1 array with the two drives. Then everything is duplicated.

 

[thardie]

In order to actually have a mirror you must set the BIOS to RAID and create a RAID1 array with the two drives. Then everything is duplicated.

Yes, I know that would work, but I've had those cheap motherboard RAID systems dump my whole array for no reason, that I'd rather trust windows mirroring than the motherboard controllers.

That also doesn't fix my current situation. Thanks anyway.

Terry

 

[pbcopter]

I'm sorry I'm not that familiar with using the software mirror. I would have thought that the repair option of the DVD would have fixed the start up for you.

Paul

 

[Tews]

Sounds like a clean install is in order....

 

[thardie]

Sounds like a clean install is in order....

Of course, that would work, but I'm not going to be the last person to use a mirror and expect my data to be safe. Seems like a major architectural flaw making the mirroring of boot drives useless.

What's really infuriating about this is I get no boot loader screen. No error, nothing. Just stops.

I've also tried installing the bootmgr set with bcdboot. I've also tried using bootsect to write the boot sectors instead of bootrec. Still no go. It's very odd.

 

[DeaconFrost]

There's been a rule on computing for many years now that states, "Never let software do the job of hardware". Software RAID is FAR less reliable than hardware RAID, even when done with a motherboard's controllers, as opposed to a dedicated one. RAID on a desktop also has little value, and has never been a method of protecting or backing up your data. Consider even a smaller example. If you accidently delete a file on a mirrored array....that file is gone.

Do yourself a favor. If you care about the data on those drives, ditch RAID altogether and get an externa USB drive. Use something like Acronis (whole system) or SyncToy (files and directories) to keep your data backed up to the USB drive. Not only is is safer, but it can be transferred to another computer for easy recovery.

 

[zigzag3143]

RAID on a desktop gives a sense of security when in fact no added protection is gained. There is always going to be a single point of failure on a desktop that if it fails you lose the data. the only way to prevent it is to have 2-blades, with 2 controllers each, with 4 or more drives, on seperate power, in seperate locations. Even then if a cpu goes your hosed.

You are more likely to be aware of the danger of losing data without the false sense of security, and backup accordingly.

Backup, Backup, Backup. Then backup the backups

Ken

 

[iseeuu]

There's been a rule on computing for many years now that states, "Never let software do the job of hardware". Software RAID is FAR less reliable than hardware RAID, even when done with a motherboard's controllers, as opposed to a dedicated one. RAID on a desktop also has little value, and has never been a method of protecting or backing up your data. Consider even a smaller example. If you accidently delete a file on a mirrored array....that file is gone.

Do yourself a favor. If you care about the data on those drives, ditch RAID altogether and get an externa USB drive. Use something like Acronis (whole system) or SyncToy (files and directories) to keep your data backed up to the USB drive. Not only is is safer, but it can be transferred to another computer for easy recovery.

Well said. I also agree wholeheartedly. My experience with RAID is that creating a bootable RAID array is not an easy thing to do and presents its own risks ie: what to do when the array fails and there is no OS to boot to fix the problem.

The software RAID included with many motherboards these days can be another layer in a backup strategy, but it is not the ultimate solution. Rather, locate your OS on its own drive, and save back-ups and files on a mirrored array. If one drive fails stick a new one in and let the software "rebuild" your data. But note you would still have to do the regular back-ups of your system which is what I think some are trying to avoid with a RAID setup. They anticipate a bullet-proof RAID mirror where they do not have to do anything except replace a hard drive occasionally. An external USB drive backup strategy is actually less expensive and safer.

Another note on this type of raid setup: The life expectancy of identical hard drives purchased from the same vendor on the same date may also be identical (their life expectancy that is), meaning both drives may fail with in a short time of each other if not at the same time. One way around this is to get different brands of drives. It also makes identifying a drive in an array easier.

thardie, your situation does not appear to be any kind of design flaw. By Windows mirror I assume you mean using the image creating utility in Windows 7? It appears the image is in tact on the remaining drive? If so that "image" is not designed for booting. It is designed so that you can now purchase a replacement hard drive and use the 7 install DVD to restore that image to your new hard drive.

Good luck!

Robert

 

[dsula]

The purpose of software raid is, that you become independent of hardware. I used to do hardware raid. Pain in the ass when after 3 years your mainboard fails and you can't get a replacement witht he same raid chipset. Linux does software raid 1 the way it's supposed to be. A complete mirror and you can take away any drive anytime and still boot the system. I was hoping windows 7 would do the same. However it looks's like it doesn't.

 

[DeaconFrost]

In the past, whenever I've tested a software RAID setup, I was able to boot with just one drive present (assuming it was a mirror). Granted, I didn't use it that often, because software RAID is still useless in my book. I'd even go so far as to say RAID of any kind on a standard desktop workstation is mostly useless, and I wouldn't even bother doing it, and haven't since the 36 GB Raptors were originally released.

Given your example above, the failure wasn't in the fact you used hardware RAID...it was that you didn't have your data backed up. Software RAID is definitely not an advantage over hardware, and shouldn't be used in place of a true RAID controller. If you simply MUST run RAID on a non-server, stick with an Intel chipset, as you would have been able to move your array to a new system.

 

[dsula]

For desktop home or small business use. ALWAYS run software raid when given the choice. It leaves you with an easy path to migrate, doesn't pin you down to a certain hardware. In case you're motherboard fails you can easily connect the harddrive to any motherboard, anywhere and recover your data. With hardware raid you can't do that. Hardware raid is good where it belongs, big company servers, where you have ample of replacement hardware and the required personel.

The rule is. Do as much as you can in software. It's cheaper, let's you migrate to newer hardware and is more flexible. Can you say virtual computing?

Too bad in windows 7 mirroring works a bit fishy. If somebody knows how to make it work, such that you can take any drive out and still boot. Please let me know. I don't think the MBR is duplicated on the second drive. But I'm guessing.

 

[DeaconFrost]

You skipped my recommendations for using Intel's RAID then. That can be moved from chipset to chipset, because the drivers are unified. It also comes standard on most Intel chipset boards now, so the cost issue goes away as well.

I'm not sure where you get your "rules" from, but I wouldn't follow them regarding software vs hardware. Your virtualization example is about the only exception, and even then it still can't be used as a blanket statement. I'm a huge fan of VMs, but there are a few cases where you need dedicated hardware.

It sounds like you were burned in the past using hardware RAID, and have made up your mind to use software RAID. I don't know about here, but on most forums, you wouldn't post something like that without having it blow up in your face.

If your only options are software RAID, then you would be crazy to be using RAID at all. The benefits of RAID pretty much go out the window at that point. I wouldn't dream of using software RAID on anything from my own personal tower to an actual server.

 

[dsula]

If your only options are software RAID, then you would be crazy to be using RAID at all. The benefits of RAID pretty much go out the window at that point. I wouldn't dream of using software RAID on anything from my own personal tower to an actual server.

I'm using software raid 1 on my small business linux server and it's a beauty. The server runs VMs. When time for HW upgrade I can buy ANY motherboard without first spending 8 hours researching the latest technology and how everything changed in the last 3 years since I installed current hardware. I hook up the HDs and it's up and running again. In case I need to upgrade harddisks, I copy the VM to the new drives and I'm back in business. No dealing with back-ups, reinstalling software. Simple and easy.

I tried to do the same thing on the desktop windows 7. However it's not that easy. I used hardware intel raid with vista before and I was hoping to finally graduate to software raid with windows 7.

Everything that can be done in software is better done in software. The only reason why somethings can't be done in software is performance, that's it. And a modern desktop has WAY enough power to handle software raid 1.

Here's a quick lit of what used to be hardware is now software:
1. sound mixing (remember gravis ultrasound, or AWE32), it's software now
2. disk data compression, it's part of the OS and software now
3. modem, modulation/demodulation, now software
4. there's even some software ADSL solution out there
5. software radio
6. and so is raid, there will be a time hardware raid will only be a distant memory
7. and I have many many more examples from industry where once expensive and pain-in-the-ass hardware was replaced with software running on a PC. (think industrial process controllers)

So if you run a small business or a home computer, buy an extra 1TB HD for $80 and use software raid. It saves you a headache in both migration and recovery.

 

[HerrKaLeun]

I don't understand what all yoru problems iwth RAID 1 are. a single HDD drom RAID 1 can bu used anywhere regardless of the RAID controller. For RAID 1 all it does it put the same data on each HDD.

with RAID 0 or others, obviously it is very importnat which controller/software you use since it strips data apart.

I don't know if I understand the thread starter, but it seems he created his system and then manually created a RAID 1? whne i built my PC I set up the RAID in BIOS (Intel chipset) and then installed everything. Even if I had had one HDD first only and then created the RAID 1, in bIOS I then woudl jsut create the RAID and BIOS would copy the data to the 2nd HDD (careful, so you don't copy the wrong way!!).

It seems he is doing something manually in software or in the OS where he selects certain partitions.

about using 2 different HDDs... the RAID 1 will be as slow as the slower of the two HDDs. So you always try to get the very same HDDs.

RAID 1 is not necessarily backup, it just let's you keep going if one HDD fails and you get a new one and back that up then. I back up weekly to a USB HDD in addition to RAID 1. (and when one HDD fails I'd back up daily till my replacement HDD ships). also a reminder for people who forget to backup. with external HDDs you need to manually do that and might forget to plug it in.

I'm not sure what you all mean by software RAID. Obvioulsy the RAID controller on a motherboard has some sort of software (firmware) and so does a dedicated professional RAID controller. Like BIOS is a software too, it just happens to be flashed to the chip. Or are you talking about someone using a Windows software to artificially create a RAID in case the board doesn't have RAID?

 

[weismannweb]

I came across this post in my travels and want to share my experience creating a software raid mirror of my system drive and windows drive. I had some issues like this post but resolved them:

http://www.sevenforums.com/tutorials/26823-convert-basic-disk-dynamic-disk-2.html#post3224823