3x 500gb WD RE2 + NF4 + Raid 5 = ???

[Quanticles]

I'd like to get about a terabyte of redundant storage, so I'm planning to buy 3x 500gb WD RE2 drives and put them in a Raid 5 on my NF4 board.

I'm booting both Windows and Linux.

The things I dont understand are...

1. The NF4 board supports Raid5. Is this accelerated? I have a dual core processor so I think I can handle it if it's not. (not important)

2. Can I still dual-boot with Windows and Linux? I keep seeing mention of drivers and whatnot. To me, a RAID should look like a single drive to the OS, it shouldnt have to know anything about the RAID.

Does anyone know if I will run into issues with dual boot?

Thanks

 

[drizzt81]

I'm booting both Windows and Linux.

The things I dont understand are...

1. The NF4 board supports Raid5. Is this accelerated? I have a dual core processor so I think I can handle it if it's not. (not important)

No. The NF4 based RAID is software. Well I like to call it 'firmware' since the OS doesn't know it's doing RAID.

2. Can I still dual-boot with Windows and Linux? I keep seeing mention of drivers and whatnot. To me, a RAID should look like a single drive to the OS, it shouldnt have to know anything about the RAID.

Does anyone know if I will run into issues with dual boot?

Thanks

Are you using a separate boot disk? Anyway, yes you will need drivers for both Windows and Linux to access that RAID volume.

 

[Madwand]

There are a couple of potential issues with dual-booting:

1. Linux might not have support for firmware RAID 5. Last I checked, it had support for NV RAID 0 and 1, but not RAID 5.

2. Even if the array is recognized by both, Linux and Windows like different file systems. So you'd probably have to install a file system that Linux doesn't like and Windows does or vice versa to see the data. Last I checked, NTFS support in Linux was OK for reading, but not so good for writing.

For many such reasons, it's generally better to have a separate file server, and pick only Linux or Windows for it, and access it over the (gigabit) network.

 

[drizzt81]

2. Even if the array is recognized by both, Linux and Windows like different file systems. So you'd probably have to install a file system that Linux doesn't like and Windows does or vice versa to see the data. Last I checked, NTFS support in Linux was OK for reading, but not so good for writing.

Actually, I have been advised that Linux can write NTFS perfectly well. I have also tested this myself and found that there is no problem writing NTFS partitions in Linux using NTFS-3g. However the linked driver does not support NTFS permissions. U_M suggests the use of the ``Captive NTFS'' driver.

Bottom line: Linux + NTFS is much less of a problem than people make it out to be.

 

[Madwand]

U_M suggests the use of the ``Captive NTFS'' driver.

I haven't used this stuff in a while; it's good to see support improving. Just a little note here -- the 3g people write that "captive-ntfs always crashes and loses files".

http://www.ntfs-3g.org/performance.html

 

[unhappy_mage]

U_M suggests the use of the ``Captive NTFS'' driver.

Note, though, that I don't currently use NTFS on any of my Linux machines; all of them are using native Linux filesystems. I know that captive is unstable, but I haven't experienced data loss with it, it just crashes and has to be remounted. With other ntfs drivers I have had data loss. It's been several years since I've tried it, though.

 

[Quanticles]

Wouldnt they be on separate partitions anyway? Or does RAID prevent that?

 

[Madwand]

Yes, you can probably get away with this using separate partitions, but you might be borked anyways if Linux doesn't yet support NV RAID 5 properly.

Any way you do this, there's some risk with this sort of stuff, and unless your RAID 5 contains nothing important or is as well backed up as it probably should be, I'd hesitate and avoid this path.

A VM could be a better alternative.

 

[Quanticles]

Yes, you can probably get away with this using separate partitions, but you might be borked anyways if Linux doesn't yet support NV RAID 5 properly.

Any way you do this, there's some risk with this sort of stuff, and unless your RAID 5 contains nothing important or is as well backed up as it probably should be, I'd hesitate and avoid this path.

A VM could be a better alternative.

Blah.. the whole point of this was to make sure I didnt lose important files due to drive failure.

Is there not a card that takes several sata inputs, and gives a sata output? The OS/motherboard should never see the RAID. This seems really silly - it makes RAID almost completely pointless for reliability.

(vm?)

 

[drizzt81]

Blah.. the whole point of this was to make sure I didnt lose important files due to drive failure.

RAID is an uptime tool. Not a replacement for backup. It protects against a single way of losing data (HDD failure) but adds a couple of ways to lose data, such as controller failure or driver problems.

Is there not a card that takes several sata inputs, and gives a sata output? The OS/motherboard should never see the RAID. This seems really silly - it makes RAID almost completely pointless for reliability.

Not really. The problem that you are encountering is not a problem inherent to RAID. It has a combination of causes:

• you want to run Linux and Windows and grant both access to the same set of disks without being willing to compromise on the filesystem (FAT32 would be well supported by both OS')
• You want to run a consumer centric RAID solution on an OS that most consumers would not touch. Without the correct driver even "normal" IDE ports would not work in Linux. It's not the OS's fault that nVidia has not created a driver that supports R-5.

(vm?)

Virtual machine. Run linux "inside" of Windows or vice versa.

 

[oplin]

I'd have a seperate machine just for your Raid stuff and access it over the lan like someone else mentioned. Think you'd be asking for more hassle than what it's worth trying to run to os's.

Try Areca they have driver support for linux.

 

[Quanticles]

I guess my point is that there should be a solution that doesn't involve the OS (no driver required).

A non-raid computer looks like this:
OS <-> Main Board <-> SATA <-> Disk Drive

An intelligent raid solution would look like this:
OS <-> Main Board <-> SATA <-> RAID Board <-> SATA <-> Several Disk Drives

A driver might only be needed in order to configure the RAID Board initially, or to replace a drive if a drive fails. Better solutions wouldn't use a driver, and instead might use another form of interface (NIC? USB?)

Regardless, in this form you could configure the RAID on one computer, move it to another computer and install whatever OSs using a multitude of file systems, etc.

 

[Aronj66]

The driver is not for the raid, it is for the controller the array is built on. All disk controllers require drivers, it's just that most non-raid controllers are natively supported in the OS. Without the driver, the OS will not recognize that disks exist raid or not. Software Management of the array is optional as far as I've ever seen. You should be able to manage the array through the controller bios.

Regardless, in this form you could configure the RAID on one computer, move it to another computer and install whatever OSs using a multitude of file systems, etc.

This is true for stand alone raid controllers. You can move the controller and disk to a new machine and the array/data will remain configured and intact.. This is not true for built-in controllers, with the possible exception of moving the disks to an identical motherboard controller.

 

[Quanticles]

This is true for stand alone raid controllers. You can move the controller and disk to a new machine and the array/data will remain configured and intact.. This is not true for built-in controllers, with the possible exception of moving the disks to an identical motherboard controller.

So this is what I want to do...

Take current computer.
Install raid controller board & driver.
Configure raid with 3 drives, blank space.
Remove previous drives from computer.
Boot using Windows Boot CD.
Install Windows using part of the space.
Boot using Linux Boot CD
Install Linux using rest of space.

Is this possible?

By the way, I'm not a person that uses Linux for shits 'n giggles - almost all of my work is done on Linux. (So this extra effort isnt pointless)

 

[drizzt81]

Is this possible?

Yes, if you get a controller that has both Windows and Linux drivers:
http://linux-ata.org/driver-status.html would be an excellent place to get this type of information.

Before you go about doing this, please do note that some people suggest that RAID-5 is a poor choice for an OS volume, unless backed by a 'good' controller. It has been suggested that RAID-5 performs poorly at non-sequential writes. Good controllers can mask this problem. It is likely cheaper to go with a RAID-0+1 or 10 setup, when comparing the price of an additional disk (~$170 for the WD5000YS at ZZF now) to the cost of a "good to excellent" controller.