NVIDIA Raid Questions

[lobosrul]

I'd like to setup NVIDIA Raid, specifically JBOD (aka spanning). I have an Nforce4 SLI board; it does not support Raid 5 BTW.

Does anyone know if you can add disks to the existing RAID array (without loss of data)?

And how portable is the RAID array? If my mobo dies one day can I move the disks to another machine, one that supports NVIDIA Raid of course.

I cannot find the answers to these questions anywhere. No where in the guide from nvidia, and I couldnt even find an answer after a google search.

[cslatt]

I don't know for sure about spanning as I've never used it, but here are the answers in regard to RAID 1:

Yes you can dynamically add drives to the array without losing data, and yes it is generally possible to read the array from another PC. It definitely works if the chipsets match (nForce4 Ultra to nForce4 Ultra, etc) and it usually works even if they don't (nForce3 to nForce4, etc). AFAIK it won't work on a non-nVidia chipset/raid controller.

[cslatt]

Sorry, I was wrong. I found a definitive answer in this PDF:

http://www.iwill.net/product_imgs/27/NVRaid_11.pdf

Can I assign a dedicated disk to a striped array/JBOD or use a free disk with
striped array/JBOD?

No, free disks and dedicated disks can be only used with a mirrored array or a striped-mirrored array.

So you can't add a free disk into a JBOD array at a later time. You can only do that with RAID 1 or RAID 0+1, etc.

[lobosrul]

Thanks for the replies cslatt. What I wanted to do was take all the data in my 2 400GB drives, and move it over to the 2 new 500GB (1 TB spanned) drives I just bought and then add the 400GB drives to the array. Oh well.

[rickgillyon]

Probably not great stuff for you to hear, but my experiences with nForce4 RAID were pretty grim. Had a 1TB striped array, nothing but trouble, errors, reboots. Swapped out the original board for another nForce4, the array was recognised and used, good for a few months but eventually errors started creeping back in, reboots/BSODs etc. too. Switched to an Intel chipset and so far, so good. Although the Intel chipset didn't recognise my array, unsurprisingly, and that was a hell of a backup to have to take and restore...

I wouldn't buy another nForce4 board, that's for sure.

[blade]

Why even bother with Raid if you're not using it for redundancy?

Sage will write to the disk with the most free space so it's already going to balance the load among your disks when recording multiple shows at once. Not to mention disk throughput is rarely a concern to begin with. You're not going to gain much if anything and you'll be adding more complexity to your setup.

[lobosrul]

Originally Posted by blade

Sage will write to the disk with the most free space so it's already going to balance the load among your disks when recording multiple shows at once.

Huh, I didnt know that. I guess I'll just have 4 independent disks.

[blade]

Originally Posted by lobosrul

Huh, I didnt know that. I guess I'll just have 4 independent disks.

Yeah, Sage is pretty smart.

[rickgillyon]

Originally Posted by blade

Why even bother with Raid if you're not using it for redundancy?

Sage will write to the disk with the most free space so it's already going to balance the load among your disks when recording multiple shows at once. Not to mention disk throughput is rarely a concern to begin with. You're not going to gain much if anything and you'll be adding more complexity to your setup.

You make a good point, and I'm almost regretting putting up my stripe again... Why didn't you say this a week ago...

On the other hand, it's quite handy having one folder for recordings, so my overnight XviD transcodes only need to look in one place. Can a DOS for statement look in two places at once? Running two loops would not be a big overhead.

[blade]

Originally Posted by rickgillyon

You make a good point, and I'm almost regretting putting up my stripe again... Why didn't you say this a week ago...

On the other hand, it's quite handy having one folder for recordings, so my overnight XviD transcodes only need to look in one place. Can a DOS for statement look in two places at once? Running two loops would not be a big overhead.

I've thought about setting up raid or jbod before, but I always talk myself out of it.

You can mount disks as folders instead of drive letters. I've checked into it in the past, but have never gotten around to trying it. I think there was even some discussion on the forums about it awhile back. For example instead of having:

D:\Recordings
E:\Recordings
F:\Recordings

You could setup:
D:\Recordings1
D:\Recordings2
D:\Recordings3

Each folder would point to a different disk. You could setup a recording folder and have each drive mounted as subfolders. I don't know if being able to scan one folder and its subfolders would be better than scanning multiple locations. Also I have no first hand experience with it, but I think I remember reading about someone using Sage that had it setup this way.

[BobPhoenix]

Originally Posted by blade

I've thought about setting up raid or jbod before, but I always talk myself out of it.

You can mount disks as folders instead of drive letters. I've checked into it in the past, but have never gotten around to trying it. I think there was even some discussion on the forums about it awhile back. For example instead of having:

D:\Recordings
E:\Recordings
F:\Recordings

You could setup:
D:\Recordings1
D:\Recordings2
D:\Recordings3

Each folder would point to a different disk. You could setup a recording folder and have each drive mounted as subfolders. I don't know if being able to scan one folder and its subfolders would be better than scanning multiple locations. Also I have no first hand experience with it, but I think I remember reading about someone using Sage that had it setup this way.

The only problem with doing this is if your Recording Directories are UNC paths and not Mapped drives like I use. When you use UNC paths the drive space cannot be calculated by SageTV correctly so it will only allow as many recordings as you have free space for on the NTFS partition you have the drives mapped too. Now if you use Mapped drives the drive space is calculated correctly by SageTV and all is well.

Also this is not a problem with SageTV as it is Windows and Networking that are causing this problem when using UNC paths.

BobP.

[blade]

Originally Posted by BobPhoenix

The only problem with doing this is if your Recording Directories are UNC paths and not Mapped drives like I use.

I had forgotten about that. At least you'd only have to map one drive.

[BobPhoenix]

Originally Posted by blade

I had forgotten about that. At least you'd only have to map one drive.

Yes. I'm not saying this is bad just something to think about if you use UNC paths. I've seen other reasons to use mapped drives instead of UNC paths (R5000 to be specific) but I have two servers and don't want to be required to map drives that don't overlap if I don't have to. I still use the mapped drive Idea to connect to from other computers but I use the individual UNC shares for the Video Directories.

So for instance I have on my MCE server:

D:\Recorded TV shared as \\mediacenter\recorded tv$
E:\Recorded TV shared as \\mediacenter\recorded tve$

and both drives are mapped to separate folders in the directory C:\Recording Folders which is shared as \\mediacenter\recording folders$

Then on my other PC's I just map a drive to the C drive share to move files around, edit, etc.

I would prefer it if Windows would make more information avaliable when you map a drive - like drive space - but I've gotten use to it.

Another option would be if you could setup shares on the drives without assigning drive letters - but I don't think that is possible.

BobP.

[blade]

Originally Posted by BobPhoenix

Yes. I'm not saying this is bad just something to think about if you use UNC paths.

Yeah, I was just thinking if someone were going to use mapped drives anyway at least this way they wouldn't have so many to contend with.

I'm currently using UNC paths myself, but sometimes I think I'd be better off with mapped drives. I've never really compared the two that closely, but it always seemed I had more problems and that Sage was at times a little sluggish with UNC paths. That was with a very low powered server (celeron 366mhz). I haven't used anything, but UNC paths since I built my new server so I don't know if it even makes a difference on my current setup.