I software RAIDed my hd's and...

IT KICKS BUTT!

I striped them using RAID-0 in Windows XP. Look at this Sandra benchmark of it now and note the comparisons to other hd's:





I was hesitant to do a software RAID, but then I thought about it, and the processor is not the bottleneck of this system... it's the slow 60gb 5400rpm hd's. The processor has more than enough speed to intelligently route the bits back and forth. And it seems to have paid off! File transfers on the hard drive are much quicker now, and it doesn't look like it uses very much of the processor at all.

It is worth of note, though, that this process causes complications with Linux, since Windows turns the harddisks into what it calls "Dynamic Disks" that it says are unreadable to every other operating system. This is not entirely true, though. If you compile the support into your kernal, Linux is able to read these drives as well.

I dunno if people have already covered this on here before, but I just wanted to post and let you all know that it works, and it seems to work well.

You need free space on each disk, and Windows will make a single, striped partition out of it. I had 50gb free on disk 1, and 55gb free on disk2, so I ended up with a 100gb striped partition and 5gb extra on my 2nd disk because the two halves of the new partition have to be the same size.

It is easy enough to do on an already-partitioned drive, so long as you have free (unpartitioned) space on both drives. You'll want to fire up Partition Magic (or Acronis PartitionExpert, which I personally recommend, from my past experience with PM) and make this space.

I believe there are HOWTOs for getting Linux to work with the harddrives after they are converted to dynamic disks (the entire disks are converted, not just the partitions you're working with). If you have trouble tracking them down, I'll try to find where I saw it.

And by the way, just because this has a picture of a benchmark in it ... does it really belong in Benchmarks? I would think this would be of interest to the general populous...

I went ahead and benchmarked my non-RAIDed C drive for you.




The first comparison system is another benchmark I did on my D right after I RAIDed it, when fewer things were running to lower the score.

First of all, the fact that it completely doubled the datarate on the harddrive is awesome. Secondly, look how the RAIDed system compares to SCSI!!

Just some more info for y'all. RAID rocks.

Introduction
RAID-0 sets up your harddrives in what is called a "striped" configuration. What this means is that for every byte you write to the hard disk, 4 bits go to one drive and 4 bits go to the other drive. It is the same for reading. So this effectively doubles the data rate of your hard drives, since each does half the work. This is often done by a hardware RAID controller... but a software RAID (like the one that we are setting up) uses your system's processor to accomplish this task.

Before you RAID your drives, I want to make sure you are aware of a few...
Possible downsides:
1. Increased risk of data loss. Since it reads and writes only half of the data to each drive, if either drive experiences a failure, then ALL of your data is lost, since you'll have nothing but HALVES of files on your working disk. This is only significant if you have mission critical data and/or you do not perform backups.
2. Increased battery consumption. This makes sense. Both harddrives are accessed for every read or write. I haven't noticed a huge effect, though.
3. Linux compatibility. Dynamic disk support must be compiled into your Linux kernel if you want to install Linux on a separate partition on your drives. Also, your new striped partition will have to be NTFS, which is not Linux friendly at this point (for writing, anyways).
4. Other OS compatibility. OSes other than WinXP, Win2000, or Linux will not be able to read these disks. 98/ME/etc will no longer work with these two drives, even if you already had them installed before you converted your drives.
5. Processor usage. Since it is a software RAID, your processor is going to split all of the data between the harddrives on every read/write. With this being said, the effect seems to be minimal on systems as fast as ours.

Benefits:
1. Speed. First and foremost, this nearly doubles the speed of your harddisk. In a P4 system with 5400rpm or 4200rpm drives, the harddisks are a huge bottleneck. This helps you get more performance out of your high-performance Sager laptop.
2. Consolidation. Another nice thing is that this allows you to use both harddisks as one partition on your computer, so you don't need lots of drive letters cluttering up My Computer.
3. Speed! Did I mention that it's really fast?

You need two hard drives that are the same speed. Mixing a 5400 rpm and a 4200 rpm would not work well. These drives need free, unpartitioned space on them. Now, if you have more than one partition (a C: for your OS and a D: for data, for example), there are two ways you can go about this.
1.) If you don't mind losing your data, you can just have Windows delete the D: or whatever partitions your need deleted when we get to the disk management part below.
2.) If you want to keep the data that's on your harddrives already, you'll have to use either Acronis PartitionExpert (recommended) or Powerquest Partition Magic to unpartition some space.

The size of your new RAID drive will be determined by the drive with the least amount of free, unpartitioned space. For example, I had 50gb free on disk 1, and 55gb free on disk 2... so the largest I could make my drive was 100gb (50gb from each drive), and I was left with 5gb free on my 2nd drive.

For those of you who wish to proceed:
Go to Control Panel, Administrative Tools, and then Computer Management. On the left, choose Disk Management. Here, you will see your harddisks and the partitions on them.

If you need to delete a partition at this point to create unpartitioned space, right-click on the graph-like representation of it and choose "Delete Volume" and when it questions you, assure it that you have not lost your mind

Ok. Now we need to convert our harddrives into shiny, new "Dynamic Disks." This is done by right-clicking on the disks in the graph at the bottom (they are called Disk0 and Disk1 here), and then choosing "Convert to Dynamic Disk" on both of them. You'll have to reboot. When it boots back up, it may bring Disk Management back up, but if it doesn't, open it again from Control Panel/Administrative Tools/Computer Management.

Now right-click on one of the amounts of free-space and choose "New Volume." In the wizard that pops up, click "Next" and then choose "Striped." It will let you set the size for the partition up until you've used all of the available space on one of the drives. From this point forward, it guides you itself.

After you reboot, you'll be the proud new owner of a RAID partition ... with transfer speeds the likes of which you've never seen! haha If you have any other questions, post here or email me at shayne@rockhill.org and I'll do my best to help. G'luck!

Sorry I didn't get back to you. I had class all morning. Yes, that is completely possible. Microsoft's official word on it is that
"when creating striped volumes, it is best to use disks that are the same size, model, and manufacturer."

You might run into a little trouble because 60gb 5400rpm drives are supposed to be slightly faster than 40gb 5400rpm drives because of aerial density. I'm not sure if that would cause huge problems or not. I suspect one drive might have to wait for a millisecond on the other, but this would surely still be faster than one, slow drive alone. G'luck!

Oh, and it is available the instant you reboot after creating it. It just shows up as D: (or whatever drive letter has been assigned to it), and there is no lag or anything, if that's what you mean.

Re: shaneOSU

Dynamic disk support does not appear to be a service (from a quick survey of my running services, so I suspect it is embedded pretty deeply into Windows. I'm sure you won't have any problems.