How to mirror disk 0

[handle789]

Hi,

My machine has a 40 gig hard drive, disk 0, with partitions C:, D:, E:, and F:. I would like to take a snapshot mirror of these partitions onto a second drive, disk 1. Then I will turn the machine off, disconnect disk 1 from the machine. Whenver disk 0 goes bad or gets so corrupted I will remove disk 0 from the machine, insert disk 1 in its place and boot up the machine again using disk 1.

I am looking at this mirroring procedure:

http://support.microsoft.com/kb/302969

I have a few questions for the techies here:

1) Is the above procedure known to work, or there are issues?

2) Is there some procedure that needs to be performed to break the dynamic disk function and mirroring before disconnecting disk 1 from the machine?

3) Will the machine boot up again with just disk 0 only and will all partitions be visible?

4) I imagine there are simpler tools out there to accomplish this snapshot mirroring task. Are there some tools like ghost.exe that can do this so that I can boot from disk 1 with all four partitions visible? Where can I download these tools?

Thanks!

 

[LWComputingMVP]

This doesn't make much sense to me... You want to mirror the drive then store it some place for potentially years before you need it... don't you think some things might happen in the interim time? Like various software updates? Data Updates? User Updates? Disks absolutely die... but not every couple of months which is the frequency they'd need to if this idea were to be practical.

does this mean you would run the server WITHOUT RAID? This is not a good idea...

If you want to create images, go buy imaging software - like Acronis products.

 

[handle789]

Hi,

The mirroring procedure at

http://support.microsoft.com/kb/302969

does not seem to be too time consuming (I am guessing as I haven't tried it yet). So I don't mind going through that procedure once every few months. The software on the server is generally static most of the time, I only need to mirror whenever there is a major software change or a lot of new data. I was wondering if the procedure above requires breaking the mirror first before removing disk 1, or if there are freeware out there that can accomplish the same task in a simpler manner.

 

[LWComputingMVP]

Let me repeat myself... are you actually planning on running this server without RAID? This is not a good idea.

Frankly, I think you're going about this all wrong.

Windows updates occur MONTHLY. This procedure will require you to shutdown the server, connect a drive, mirror it, then remove it. The mirror process takes a couple of hours for a drive of that size if I remember correctly.

Why are you so reluctant to do this in a more common way?

 

[handle789]

Yes, it is running without a RAID because it is not that important to require a RAID. I just want a quick way to recover if all that is required is sticking in disk 1 in place of disk 0. That is what the question in this thread is about; you are side tracking to a different issue.

 

[LWComputingMVP]

Actually, I'm an experienced systems administrator who feels running almost any server without RAID is a bad idea. Further, as I've stated, your procedure, though it may work, is more than likely going to be more of a waste of time than a backup. If you want an image of the system, fine... but don't use go about it this way - get PROPER imaging software than can be automated and take appropriate backups.

If the data is not important enough for RAID, why make a mirror/imaging backup at all. Run a periodic tape backup over the data and if necessary, rebuild the server when it fails. I've managed dozens of servers and they simply don't die frequently... yes it happens, but for a server that you apparently can live without for a period of time, you're just wasting your time trying to do periodic mirrors and breaking them when all you'd need to do is one reinstall and a restore IF the server ever fails. (Don't know how long it takes for you to build a server; takes me about 90 minutes... and the restores are largely automated.

 

[handle789]

This is a test server. Once in a while it gets corrupted and takes a long time to reinstall all the software (the OS part is easy). If all it takes is to switch the ribbon cable from disk 0 to disk 1, then it's a quick way to recover. Seems like you don't have any good suggestions or answers to the original questions.

 

[LWComputingMVP]

Why do people refuse to provide a context in the initial question?

That makes answering appropriately so difficult.

If this is a test server, why haven't you tested this? A mirror is an exact copy of the drive. Think about how it works - if a drive fails, the system keeps running. So in short, yes, it should work fine...

But why would you use a hardware system as a test system? Virtual Machines are FAR easier to backup and create test environments from.

 

[handle789]

You've asked me more questions than I asked you. If it were a production server, it would have been much better protected. Sounds like you haven't worked in a SAN environment. The approach I am using here is kind of similar to what they called snapshot, flash copy, BCV, establish/split, ... but it's done manually. The VM environment is completely off the track. This machine only has a 40 GB drive, 1 GB RAM and a rather slow CPU, and I have a couple of spare 40 Gig HDs. I am just looking for a simple solution, and I am about to test it after getting the answers to the four clearly stated questions above. I was wondering if a procedure to break the mirror (split) is needed, but could not find info on this. Generally you would like to establish the mirror and split the mirror in a clean manner, not just by pulling the second drive off.

 

[kmcferrin]

Let me first state that I have never used software mirrors. If it's worth doing, it's worth doing in hardware.

Secondly, I would suggest that you look into some sort of disk-based imaging system (like Acronis) to do what you are trying to achieve. Using Acronis to do an image-based backup is much like being able to do snaps/flash copies/whatever your brand of SAN calls it, as it is an exact copy of a disk.

Thirdly, I highly recommend that everyone use virtual environments for testing. It makes the entire process much easier because you can deploy a fresh machine in minutes instead of hours. Also, if you're using a virtual machine, you can make backups of the virtual machine file on the disk to get disk images/snaps without having to resort to convoluted mirror/breaking procedures, backup/restores, etc. On top of that, you can be running multiple test servers on a single piece of hardware, which means you can do more with less.

Additionally, entry-level virtualization software is free. You can use tools like Microsoft Virtual PC or VMWare Virtual Server, which are both freely available for download. I would recommend VMWare because I think that their platform is more robust, and also because they have a free Physical to Virtual converter tool that will allow you to make a virtual machine file from a physical server. If you already have a physical server built you could run the P2V tool and start testing in a virtualized environment.

Fourthly, I think that the reason that you're not getting answers to the specific questions that you want answered is because what you are trying to do is very peculiar. Add to that the fact that there are several much easier ways of achieving the same goal and you are unlikely to find someone who has done what you are asking about.

Finally, the procedure for booting from a software mirror under Windows after the primary drive has failed is here:

http://support.microsoft.com/kb/113977/EN-US/

Additional info is here:

http://support.microsoft.com/kb/114779/EN-US/

Both were linked in your original article.

From the looks of things, what you are suggesting will not work. It appears that Windows designates one of the drives as the primary, while the other is the mirror. The mirrored disk doesn't even show up as having a bootable OS on it. With hardware mirroring both drives are usually treated equally.

It appears that your current drive would be the primary and your offline copy would be the mirror. I'm not sure if you would be able to even boot from the primary without the mirror being present, or if you did it may require a boot floppy. It appears that if your primary were corrupted then you would need to boot your mirrored "backup" (and I use that term loosely) from a floppy disk, and then make some changes.

In short, I don't think that this solution will work, this isn't the solution that you're looking for, etc.

Suggestions (in order of preference)

Use VMWare and virtualize your test box.

Use disk-imaging software to make an image-based backup.

Buy a cheap hardware RAID controller that can do mirroring.

With any of the solutions above you can use your multiple 40GB disk drives (perhaps even with software RAID in the first two cases) to get more disk space for storing images, etc.

 

[pagy]

handle789,

You have been given some good advice here by lwcomputing and kmcferrin which I recommend you follow, the use of virtual machines for test servers is the best way to go or use an imaging product like Acronis for imaging the server. There are a few imaging products available for servers, use google to find them.

At best what you want to do is problematic and at worst just won't work.

Paul

MCSE 2003

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
Albert Einstein

 

[handle789]

Thanks for the responses. I am checking on the feasibility of this mirroring approach because it is free. If you have suggestions for some other freeware that you have used that can accomplish the same tasks and in a better manner, I'd appreciate it (this is question # 4 above). Acronis is not free.

This machine could as well be an XP box has it not been for some software that require a 2000 server. I was hoping that someone might have used this approach before and can tell me whether it will work or not before I try doing it, as it may cause a problem later on if there isn't any procedure to break the mirror and boot from the remaining disk 0 (or disk 1).

I don't have any machine with a lot of capacity to use as vmware machine right now. Anyway, since the current box is already there with all the software installed, I might as well use it rather than going through the whole procedure of installing everything from scratch.

 

[pagy]

I found these using google

http://selfimage.excelcia.org/

http://www.feyrer.de/g4u/

I've used g4u before, it works but it will take quite some time, depending on your network spped and disk sizes, to create/download images.

Paul

MCSE 2003

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
Albert Einstein

 

[pagy]

Or this

http://www.drivesnapshot.de/en/

Paul

MCSE 2003

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
Albert Einstein

 

[kmcferrin]

I'm not sure what your requirements are, but for the free version of VMWare server your main requirements are going to be disk and memory. It sounds like you have enough disk already. With memory the only requirement is to have enough for the gost + the guest OSes. On a 1 GB machine you can allocate 256-384 MB for the host (Windows XP would work) and the remaining 640-768 MB to the guest, or break it up among multiple guests. It will of course run slower than a native machine, but unless you're running stress tests then performance isn't usually an issue on test machines.

 

[handle789]

Thanks for the pointers, I'll explore them. g4u looks interesting, but it requires more than one machine. I built a vmware machine a year ago on top of a windows 2000 server and then set up a couple of guests running linux and windows 2000 server. Response to key strokes and mouse drags was at a snail pace level. I didn't have much time to explore further and gave up on playing with it. The current windows 2000 machine is using almost 30 gig of the 40 available, and it will take a while if I were to set up an identical virtual machine on vmware, plus a lot more time to make it work fast like the current machine.

 

[LWComputingMVP]

Sounds like you didn't install the add-on tools for the VMWare client - that improves performance significantly.

http://kb.vmware.com/selfservice/viewContent.do?externalId=340