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seeker
03-20-06, 06:39 PM
There is something that I remain quite confused about. When creating a striped raid array, I have tried creating twin partitions on both of the drives in the array, and also only on the first drive. I have found no difference in performance, or the way that the array appears on any of the monitoring programs, either in Windows, Linux or third party. This leaves me wondering exactly how the array utilizes the second drive in the array? If I only partition a portion of the first SATA. how will the second SATA's space be utilized?

john19055
03-21-06, 03:44 AM
If you have a raid setup as stripped then it will combine both harddrives to be one big one ,the stripped every what yo set is at is how it writes to the harddrives,like if you set it to 32k then if you have a file bigger then that it will write part of it on one drive and part of it on the second drive,which it speeds up the read and write of the harddrives when set at Raid stripped.

seeker
03-21-06, 03:58 AM
I understand how the stripe raid works, but my question is only about the partitioning. For example, I have 2 80GB drives combined in the stripe. If I set a partition of 25GBs, will that use identical amounts of space on both drives. Or to go farther, let's say that I set multiple partitions for different OSs, will the array be able to keep the data from one OS separate from the other OSs? Or, another way of putting it, when you creat a partition, is the partition produced exactly identical on both drives?

seeker
03-21-06, 07:48 AM
There is a good RAID tutorial here:

http://www.acnc.com/04_01_00.html

According to the site it says about RAID0
"RAID 0 implements a striped disk array, the data is broken down into blocks and each block is written to a separate disk drive"

Hope it helps...
Thanks for the link, I'll read it after waking up. However, your quote still only tells me what I already know. But I have asked it about everyway that I can think of, so reiterating won't help.

Q
03-21-06, 08:55 PM
If you've implemented striped raid correctly, you really shouldn't see two individual drives. It should be seen as one physical drive by the OS. You wouldn't be able to set partitions on individual drives. On the one virtual drive that raid creates, you could partition that as you wish, but it would be just like partitioning one drive.

I hope this answers the question:
"If I only partition a portion of the first SATA. how will the second SATA's space be utilized?"

Under striped raid, it is impossible to partion only a portion of the first SATA drive. When you create a partition on a striped raid array, it is split between the two drives.

seeker
03-21-06, 09:28 PM
If you've implemented striped raid correctly, you really shouldn't see two individual drives. It should be seen as one physical drive by the OS. You wouldn't be able to set partitions on individual drives. On the one virtual drive that raid creates, you could partition that as you wish, but it would be just like partitioning one drive.

I hope this answers the question:
"If I only partition a portion of the first SATA. how will the second SATA's space be utilized?"

Under striped raid, it is impossible to partion only a portion of the first SATA drive. When you create a partition on a striped raid array, it is split between the two drives.
I think that I understood what you said, but since I'm a bit thick headed, I would like to clarify. By virtual drive, you are referring to the resultant drive created by the array, i.e. 2 x 80GB = a 160GB virtual drive? If I set a partition on this virtual drive, that partition would be mirrored on both physical drives. Therefore, I could set as many partitions as I desire, on the virtual drive...yes? Thus, I could install multiple OSs on the virtual drive without a problem.

If what I have said is true, it still leaves one question. If the virtual drive is set as a striped array, by the initial setup in the BIOS and by the original OS (WinXP), and I then install Linux in a secondary partition, but do not set that installation to use raid, would the data still be split between the physical drives? If that is true, then it would seem as though Linux would not need any special setup to use the array that already exists, but from past discussions, this is not true. I have setup Linux as the second OS both with and without the Linux raid function, and I can't tell the difference in any performance or data monitoring.

I may be asking too many questions, but without these, I'll never feel confident that I really understand what is going on.