Two disks one volume?

[osuman]

I have a Western Digital 20 gig drive running Win 2k on a single NTFS partition. What I would like to do is buy a 40 or 60 gig drive and put it as the slave with my other one. However, I would like to make both drives one volume (C), enabling me to keep adding to directories rather than splitting things up and keeping track of it all that way. I have looked around a little and found that this is called RAID striping or spanning? Anyway, this leads me to a couple of questions.

1) Can I do this with some sort of software or is there hardware involved to make it work? (My mobo doesn't support RAID)

2) Can it be implemented without data loss. IE, having to format and reinstall the OS?

3) Has anyone heard of any good programs/devices or had any experience with such a setup?

4) What sort of other considerations are there such as, performance and loss of space due to slack caused by oversized clusters.

Thanks Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[Mudassar]

Good Question. I am still researching about this and will let you know when I have the full info.

I also hear that it would almost double the speed of the computer! However the downside of that is that you cannot decide to take the hard drive out unless if you want to format everything. -----------------
MK

Everybody should use AntiVirus! Are you protected now?

 

[Mudassar]

I found some good infomation about it. Link given at bottom:

What is RAID?

For those of you that are not familiar with RAID, it is a way of combining 2 or more drives in an array as a ‘combination’ of drives seen as one by the system. This can be used for data security (keeping two constantly up to date copies of the data), speed (spreading the load over more then one drive and using the maximum sustained data transfer rate from each drive to give a higher total rate) or just to combine multiple drives in to ‘one’ drive larger drive. There are a number of different RAID modes, and not all controllers support all modes. I’ll briefly cover three of what I think would be the more common for home or small business use below:

RAID 0 (Striping) interleaves sectors of data between the drives in the array. So if you have two 20GB hard disks, data is written alternating between the drives on the array. Neither drive holds all the data (just every other piece) and your total drive space is twice the size of the smallest drive (40GB). This can give you more data throughput, since you are essentially using two drives as one and your data throughput could be close to double that of a single drive. The problem is, if one drive fails you lose all the data. But if you were running just one drive as most users do normally, you’d be in the same position, so that may be a non-issue. More than 2 drives can be used and performance should improve with more drives.

RAID 1 (Mirroring) is the one I think of most when using RAID. It gives data security by writing the data to both drives and some speed by reading from whichever drive head is closest to the data. If one drive fails you still have all your data on the other drive. Great for a business or server installation where loss of data and down time reloading from a backup is something you can’t put up with.

RAID 0+1 (Mirroring and Striping) can be used to combine the best of RAID 0 and 1, though it needs three drives to do so. It will allow for reading and writing in parallel along with data duplication.

You can also change the block size, so in RAID 0 it would write X amount of data on one drive, then the same on the other(s), constantly switching back and forth between the drives. The HPT 370 I used defaulted to 64K, but I also tested at 16K. You could ‘tune’ your system by testing with different sizes finding the optimum size for your particular use (sounds like a lot of work to me).

http://www.realworldtech.com/page.cfm?ArticleID=RWT022201021241

-----------------
MK

Everybody should use AntiVirus! Are you protected now?

 

[rfeenie]

RAID aside, why dont you use partition magic to squeeze both drives as the c: drive ??? made by symatec.

Rob If in doubt get the Ball Pein Hammer out

 

[osuman]

Partition Magic is actually made by Powerquest. I have it and have looked at it but you can only merge partitions on the same drive. Or so I believe.

Thanks for the info Mudassar. You said "...the and your total drive space is twice the size of the smallest drive..." Does this mean if I get a 40 gig drive it will only be able to use 20 of it in the RAID process, since I have a 20 gig right now? Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[Alt255]

Hmmm... I'm feeling a bit nostalgic... this sort of thing could be accomplished with a single command from (I believe) MS-DOS versions 2 through 5.

[tt]JOIN D: C:\D-DRIVE[/tt] forced the contents of the "D:" drive to appear in the "C:\D-DRIVE" directory. For all practical purposes, physical drive D: was joined to the C: drive. References to drive D: resulted in "invalid drive assignment" errors and any attempt to read from or write to the C:\D-DRIVE directory were redirected to the now, nonexistent D: drive.

Of course, the effects produced by the JOIN command were mere illusions, designed for convenience, much in the same way that RAID systems are designed for convenience. C:\D-DRIVE was simply an alias for the root directory of a separate physical disk. By analogy, RAID performs the same sort of trick, but at a much lower level and with much greater efficiency. Sectors on separate disks are JOINed into what appears to be a single disk.

I guess my point in these ruminations is that, at the lowest level, DOS has changed very little since version 5.0 and I am fairly confident that this sort of disk hocus-pocus is still possible with some of the more recent OSes.

Naturally, Justin, my comments are based on your original question. You wanted to make the contents of two disks appear to be on one volume. You didn't want to split disk writes among multiple drives or mirror them redundantly. Basically, you were hoping to create the illusion of convenience. Would you use the JOIN command? (I did, but only to confuse my co-workers.)

Please don't take offense... I have worked with users who had no idea how many drives were installed in their computer. All that they cared about was opening files, modifying files, saving files and then opening them again. When I asked where they kept certain items they would tell me, "Oh, that's under My Computer."

Basically, one huge, friendly filing cabinet called Windows.

I'm not clear about what you are trying to accomplish, aside from the convenience of making two volumes appear to be one volume. I think you should ask yourself that question before you start throwing money around. You should also ask whether you aren't looking for a way to create a convenience that ships, fully functional, with every copy of Windows: My Computer.

Alt255@Vorpalcom.Intranets.com​

 

[osuman]

Alt,
Thanks for the detailed response. If I understand correctly you are saying that using this command creates a directory under the C drive in My Computer which is essentially a type of "link" (for lack of better term) that is the second drive. I don't think this would accomplish what I'm trying to do. Let's consider the following example.

The various documents that I keep are conveniently stored in the My Documents folder on the Desktop. However, the true directory of these files is C:\Documents and Settings\Administrator\My Documents. Now lets say, for example, that my disk is full to capacity and I want to keep a large file in this directory.

If I were to use the "join" command I would be unable to put this file in that directory because it doesn't reside in the D-Drive root directory. Again, this is what I understand of what your wrote.

In short, what I want to be able to do is to keep adding to the current directories without splitting things up between two partitions or root directories. Would any flavor of RAID be able to accomplish this?

I hope all this made sense. Again thanks for your replies. Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[rfeenie]

why dont you just move all your data files to the 2nd 40gig hard drive, thats easy enough and should keep you going for aegon's. If in doubt get the Ball Pein Hammer out

 

[Mudassar]

No Ousman, Basically means that your hard drive will be doubled if you have two 20gig hard drives. BUT if both sizes are different, and you decide to use RAID 0 (Striping) then it will cause a conflict. I am not sure what could happen and I recommended that since both drives are different sizes, you should use RAID 1 (Mirroring). This way you get a total of 60GB. Downside is that you don't get speed improvements.

RAID 1 (Mirroring) will just combine the drives.
RAID 0 (Striping) will not only combine the drives but both drives function at the same time so you get speed improvement.
-----------------
MK

Everybody should use AntiVirus! Are you protected now?

 

[osuman]

Isn't mirroring keeping a duplicate copy on a second drive for servers where data protection is important? And yes, I could make an image and move it to the larger drive, however, I thought I could make both usable as one it would be the way to go. It sounds though as if this isn't very easy or inexpensive. Anyone know what methods there are to implement it. Do I need controller hardware or will some sort of software do it for me? Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[teknoguy]

go to

http://www.promise.com

then click on products. They may have your answer. good luck

 

[osuman]

Thanks for the site. It looks like RAID 0 is what I'm after. Apperently, if you span the disks then you can use the full capacity of all of them, rather than twice the smallest disk, but you don't get any improved speed out of it. I'm really not too concerned about how fast it goes, so it looks like I know what I need whenever I'm ready to upgrade.

Thanks again everyone for your help. Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[DeanSpencer]

If you are using Win2k and you make your drives NTFS you can mount your 2nd hard drive as a directory on your 1st hard drive. To me this is the best way on a Win2kPro workstation. In my humble opinion raid should only be used with very critcal data on servers and high end workstations.

 

[osuman]

Can I mount it to the first drive without specifying a directory? Allowing the space of the second to exist on the C: partition so that I can continue to add to directories rather than splitting it between directories. Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[DeanSpencer]

Here is a link to MS's website that tells all about Win2kPro disk management.

http://www.microsoft.com/technet/win2000/bestperf.asp

 

[ATCal]

Are you running Win2k Pro or Server?

Your main question should be the value of your data.
Professional natively only supports RAID 0 and spanned volumes (combining space on multiple drives to create one)without a dedicated RAID controller. With both of these methods, you risk the loss of all data should one drive in the array fail.
If you have a good backup strategy, one could just create a large volume. In all honesty however, the safe bet is to leave it as two drives. Unless you have a huge database or extremely large AV files that need to span multiple drives, the inconvenience that you mention should be worth the peace of mind.

Al
atc-computing@home.com

 

[osuman]

You say that Professional (which I have) only supports it without a controller. Does this mean that it's possible to set up without a controller? If so, how? The only way that I've seen you can actually set it up is with a controller card. I'm not really to interested in speed or data saftey. I back up everything that I don't want to lose, so if one drive goes, it's pretty much all the same to me. Someone else posted a link to an MS article that says 2000 supports it, but what does just "supporting" it entail?
Thanks Justin

Feel free to email me at:
beckham@mailbox.orst.edu

"3 out of 4 people make up 75% of the population."

 

[ATCal]

Basically, 2k Pro requires a RAID controller to do RAID 1 (mirror) or RAID 5 (striping with parity- which is by far the most reliable).
The 2k Pro software alone will allow you through disk manager to expand a volume across multiple drives so that you only see one drive under my computer or shared across the network.

Al
atc-computing@home.com