RAID 5 and Proper Boot Disc/Partition

[jethrodesign]

Hi, I'm building a new system most likely based on an Asus P5W or P5B (still waiting to see which is better). Both have the Intel chipset that supports a SATA RAID 5 setup.

I would like to get 3 really good SATA drives and build a RAID 5 for my main storage. I'm sick of drives crashing and all of the hassle it brings, especially with ever-increasing storage sizes.

- My question is - would I need to put my operating system boot drive on a seperate drive, or could it be on a 'different partition' on the same RAID array?

I read something about the Intel chipset allowing multiple RAIDs across the same set of discs.

- Is this a similar concept to multiple partitions on a single drive?

- If I'm planning on doing audio recording or video to the main RAID 5 storage area, what would be the performance hit of having the boot drive be on either the same RAID, or a seperate RAID across the same discs?

- If, for performance sake, I make the boot drive a separate drive, can I setup a RAID 1 concept across 2 equal partitions on 1 drive? I don't want to lose the data on my boot drive either, but 5 drives in my machine is just too much (3 for storage, 2 for boot disc)!

THANKS for any help! I'm a bit new to RAIDs and just want to make sure I understand things correctly. I know the usual way to do audio is to have a separate drive for audio from the main boot drive.

 

[mkaibear]

>Could it be on a 'different partition'

Yes.

>multiple RAIDs across the same set of discs // similar concept to multiple partitons

Sort of.

Normal RAID works on a disk-by-disk basis - in its simplest form you stick two disks together and mirror the data.

Linux (& Windows) software RAID, and the Intel chipset RAID allows you to, say, take two 80Gb drives, split each one into 2 40Gb partitions, and then RAID 1 two of the partitions for redundancy and RAID 0 two of the partitions for speed.

You end up with;

Disk 1 Partition 1 is in a RAID 0 with Disk 2 Partition 1
Disk 1 Partition 2 is in a RAID 1 with Disk 2 Partition 2

It's a bit more flexible than that, of course, but that's the basic idea.

>planning on audio recording or video

I wouldn't use RAID 5 if I was doing audio recording or video. The write overhead is far too big (because of the Xor calculations).

I would have 2 drives in a RAID 0 for your audio and video work, and 2 drives in a RAID 1 for your O/S and "data storage".

>RAID across 2 partitions on 1 disk.

Yes, you can do this. It's a pretty dumb idea! There's no hardware redundancy - so if the disk fails you still lose everything. (instead of "Redundant Array of Inexpensive Disks" you would have a "Non-redundant non-array of One Inexpensive Disk". So possibly a NOID).

 

[jethrodesign]

Thanks for all of the tips!

- So how much perfromance is 'lost' when using a RAID 5 as compared to a single stand-alone drive? Is there a resource where I can find this info easily?

Thanks. I really want to have redundancy and security against losing data. I've heard that a RAID 1 is a real performance stealer compared to a single drive. But I was hoping a RAID 5 may do better.

- Any other ideas for having decent performance for audio/video (at least the same as a standard 7200rpm SATA drive), while at the same time getting the peace of mind of having safe redundancy?

- And what would be the best solution (performance/security) for the boot/OS partition?

THANKS AGAIN FOR ANY HELP! If there are any great resources where I can get the basics on this stuff explained, that may be helpful as well.

 

[geofelt]

For a tutorial on raid go to storagereview.com
http://www.storagereview.com/guide2000/ref/hdd/perf/raid/index.html
The use of raid does not eliminate the need for backup to an external destination. If you have such backup, how much do you need the rapid recovery capabilities of raid?

 

[mkaibear]

>resource where I can find this info easily

It depends on the controller, the disks, and what you're doing with it. Because of the range of factors I seriously doubt you'd find a resource that will tell you definitively.

>RAID 1 is a real performance stealer

RAID 1 doesn't affect the performance of a single drive (at least, not with SATA - having 2 IDE drives on 1 controller in RAID 1 would have an effect). RAID 1 may even make things faster.

>decent performance, peace of mind

RAID 1.

>safe redundancy

An external hard drive and regular backups to recordable DVD.