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westyellmt

Adding RAID 1 to existing WinXP system.

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A friend is planning to add a Promise RAID card to his month old Dell P4 WinXP system. He's currently running 1 x 120GB IDE WD HDD.

Is it possible to install the Promise card and second WD drive in a RAID 1 configuration within the current WindowsXP installation or will he have to install the Promise controller and 2nd drive and then re-install WindowsXP?

As you can tell from the above I have zero experience with RAID configs.

Thanks for any suggestions, tips, or help.

Harry

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I think most low-end IDE RAID controllers will be able to do this. They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration. For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

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I think most low-end IDE RAID controllers will be able to do this.  They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration.  For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

That last part doesn't sound smart (performance and security-wise).

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I think most low-end IDE RAID controllers will be able to do this.  They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration.  For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

That last part doesn't sound smart (performance and security-wise).

Why not?

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Single drive can be thought as it would be in single drive RAID0 (as Chew said). Makes perfect sense to me, but this feature is seen only in high-end SCSI controllers.

westyellmt:

Promise can do "security array with existing data", in other words You can have a drive with existing data and the controller will duplicate it when the array is created.

Word of warning: I did this with my system, and somehow I ended up copying the contents of the wrong drive to the other. So make sure that You source the right drive. (Connect only one drive to the card, and check what id it gets in the BIOS of the card)

Install the drivers to the OS before making the swap.

Cheers,

Jan

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Very helpful info, thanks a lot.

One other question; is it necessary to fdisk & format the new HDD before installing it on the controller or will there be an option to do that as part of creating the array?

Harry

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I think most low-end IDE RAID controllers will be able to do this.  They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration.  For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

That last part doesn't sound smart (performance and security-wise).

Why not?

By first migrating from a 1 drive RAID 0 array to a 2 drive RAID 0 array half of the blocks needs to be moved to the other drive and half of the blocks needs to be moved on the same drive.

By then migrating to a 2 drive RAID 1 array, half of the blocks need to be moved again on both drives and half of the blocks need to be copied to the other drives.

During those operations the array is vulnerable.

Simply moving from 1 drive RAID 1 to two drive RAID 1 just requires a copy of all blocks.

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I think most low-end IDE RAID controllers will be able to do this.  They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration.  For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

That last part doesn't sound smart (performance and security-wise).

Why not?

By first migrating from a 1 drive RAID 0 array to a 2 drive RAID 0 array half of the blocks needs to be moved to the other drive and half of the blocks needs to be moved on the same drive.

By then migrating to a 2 drive RAID 1 array, half of the blocks need to be moved again on both drives and half of the blocks need to be copied to the other drives.

During those operations the array is vulnerable.

Simply moving from 1 drive RAID 1 to two drive RAID 1 just requires a copy of all blocks.

Many high end controllers require you to define a single drive as RAID 0, simply to operate. When you migrate to a 2 drive RAID 1 it should just be a simple data copy to the new drive. I don't think it converts to a two drive RAID 0 and then into a RAID 1.

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I think most low-end IDE RAID controllers will be able to do this.  They can take an existing drive, pair it with a new drive and duplicate the data to it, and use the pair in RAID 1 without affecting the data or having to reinstall.

Most high-end controllers don't work this way, but can work around it if they support RAID level migration.  For example, my Compaq controller can convert from a single drive RAID 0 (the method it uses to present a single drive) to a two drive RAID 1 by first adding a new drive to the array set then migrating from RAID 0 to RAID 1.

That last part doesn't sound smart (performance and security-wise).

Why not?

By first migrating from a 1 drive RAID 0 array to a 2 drive RAID 0 array half of the blocks needs to be moved to the other drive and half of the blocks needs to be moved on the same drive.

By then migrating to a 2 drive RAID 1 array, half of the blocks need to be moved again on both drives and half of the blocks need to be copied to the other drives.

During those operations the array is vulnerable.

Simply moving from 1 drive RAID 1 to two drive RAID 1 just requires a copy of all blocks.

Many high end controllers require you to define a single drive as RAID 0, simply to operate. When you migrate to a 2 drive RAID 1 it should just be a simple data copy to the new drive. I don't think it converts to a two drive RAID 0 and then into a RAID 1.

That's right. I think my definition wasn't very clear. The way the Compaq controllers work is this.

Arrays are defined as a group of physical drives grouped together. This creates a certain amount of available space. You then takes chunks of that available space and assign a RAID level to it, creating a Logical Drive. It's therefore possible to have two physical drives, use the first half of each drive for RAID 1 and the second half of each drive as RAID 0. Not necessarily recommended, but possible.

So the process for what I mentioned earlier is this. Let's use 9GB drives an an example. You start of with an Array with one 9GB drive, giving you 9GB available space. You assign all of that space to a single 9GB RAID 0 Logical Drive. It's not technically RAID 0, but that's how these controllers define the use of a single drive.

Now, you add your new 9GB drive to the Array. You now have 9GB used in your RAID 0 Logical Drive, and 9GB unused. If you leave it at that, it will migrate the data so that half of each physical drive is used. But that's not what we're doing here. You select the Migrate option and choose RAID 1. The controller now proceeds to mirror the data from the first drive to the new. This can all be performed live. While the process is happening, it still presents just the data from the first drive only so you're in exactly the same position as you were originally with a single drive and no redundancy.

Of course, it's always recommended that you have a backup of all data on the drives before starting this. However, I've seen the operation performed many times. And not just from RAID 0 to RAID 1. The controllers support migrating between RAID 0, 1, 10, and 5. They also support live stripe size migration and expanding Logical Drive size.

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Of course, it's always recommended that you have a backup of all data on the drives before starting this. However, I've seen the operation performed many times. And not just from RAID 0 to RAID 1.  The controllers support migrating between RAID 0, 1, 10, and 5. They also support live stripe size migration and expanding Logical Drive size.

Just wanted to add to the bolded comment. This should have mentioned WITHOUT FAILURE.

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Very helpful info, thanks a lot.

One other question; is it necessary to fdisk & format the new HDD before installing it on the controller or will there be an option to do that as part of creating the array?

You format/fdisk AFTER creating the array. Once an array is configured by a controller it presents the array to the rest of the system as if it were a standard drive. So after creating the array, do as you would do to a standard drive.

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np, I JUST HOPE IT HELPS

THX MANN

mann my friend, I'm just wondering what your contribution to this thread has been? Usually one would only say such a thing if one has actually helped someone.

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Thank you all very much.

Tomorrow I'll be helping him install the Promise TX2000 card and second HDD. I think I'll start by Ghosting his current drive to CD-R's as an insurance policy and then proceed with the RAID install.

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