Burning/Extracting from/to unRAID

[Stokkes]

Few questions for the experts out there before I move my configuration to unRAID.

 

1) I currently have a Win2003 storage server running a 5x500GB RAID5 on a Promise SuperTrak EX8350 hardware controller. This configuration allows me to burn disc images (DVD/CD/DVD+DL) directly from the network at full 8X/16X speed. I'm just wondering, can unRAID perform similarly? I need to be able to burn from the network.

 

2) Extracting directly to or from the unRAID share. How is performance when doing extracting operations either directly to the unRAID share or to a local machine connected via GigE? The same could be said for creating DVD images from a Windows machine directly to the unRAID share..

 

3) With unRAID (i'm not 100% sure on this one), can all your drives act as 1 volume/share as a true RAID would give? if I have 5x500GB drives, will each drive appear as a separate share or is there a way to "concatenate" / daisy-chain them to give a 2TB contiguous block of usage space with 1 drive as parity?

 

That's it (for now!)

 

Thanks!

 

 

[Billped]

While I have not yet burned FROM the unraid (read), I have ripped TO the unraid (write).  Since write performance is not as good as read, I would surmise that it should work.  I am running GigE and get ~25MB/sec reads and ~10MB/sec writes (Bytes, not bits).  I know 8X should work for you, but 16X is ~20MB/sec (IIRC) so you are cutting it close.  Buffering should help, of course.

 

Unraid was not designed with ultimate write performance as a high priority item.

 

Yes, you can have folders that bridge drives to give you one huge drive.  It is optional - you will be presented with individual drives by default and user shares (basically concatenation) as an option.

 

 

Bill

 

 

[Stokkes]

Hmm.. write performance is worse than I thought it would be. 10MB/s doesn't even saturate a 100mbit LAN.

 

I'm currently losing sleep over this NAS setup. It's either this or a ReadyNAS. I primarily want future expansion and readynas / unraid seem to be the only viable solution, the downside being ReadyNAS only supports 4 drives, so once I've filled 4x500, i'd have to buy 4x750 or 4x1TB  to increase the space.

 

 

[Billped]

My 10MB/sec result was from a very informal test.  Basically I used windows copy/paste and moved an ISO from my WindowsPC to the Unraid and calc'd the effective speed.

 

I have iozone to do more specific tests but haven't run it yet.  My gut tells me that something is capping me and it could be my GigE card in my windows box.  Netgear (Realtek, IIRC).

 

 

Bill

[Stokkes]

Guess my best bet would be the try the 3 drive version.

 

I have 2 OSX boxes here (Mac mini theatre and MBP as my primary machine) and I'm a bit worried about network performance with OSX since unraid doesn't support AFP or NFS and only SMB.

 

I really really love the idea of being able to just throw extra drives into the machine and have the space grow, all the while having parity and knowing that the files are also accessible directly on the drive.

 

 

 

[Billped]

BTW, I am running iozone right now ... stay tuned.

 

 

Bill

[BLKMGK]

Ripping TO the unRAID? Slow as molassas for me - I rip to local storage and copy over all the disks while I sleep. Burning FROM the unRAID? No problem! I keep copies of much of my software in ISO format on an unRAID share to burn when needed - I've never had an underrun.

[Stokkes]

Buffer underruns don't happen anymore with today's burners. All they do is adjust the burn speed to compensate.. You'd almost need to do speed tests from to see how long an 8X burn takes and a 16X burn takes. a 16X burn is about 22-24MB/s, so while you could theoretically "burn" at 16X, if the network doesn't keep up, your burner will automatically adjust its speed to compensate for the buffer being filled with data at the rate it's getting it from the unRaid server.

 

 

 

[bubbaQ]

FWIW, I have a 16x burner, and I have it set to burn at 8x.  Even when burning from locally-stored files:

 

1) I found the 16x burned disks (with good media) were not reliable for reading in some other drives.

2) I occasionally had coasters at 16x... never at 8x.

3) With the lead in, lead out, and other housekeeping, 16x only shaved about 2 minutes off of total burn time at 8x.

4) At 16X, I practically had to stop all other use of the PC till it was done.  At 8x, I can browse and read mail.... just nothing disk intensive.

[BLKMGK]

Buffer underruns don't happen anymore with today's burners. All they do is adjust the burn speed to compensate.. You'd almost need to do speed tests from to see how long an 8X burn takes and a 16X burn takes. a 16X burn is about 22-24MB/s, so while you could theoretically "burn" at 16X, if the network doesn't keep up, your burner will automatically adjust its speed to compensate for the buffer being filled with data at the rate it's getting it from the unRaid server.

 

Thanks for that explanation but actually I understand how it works. As it happens I've got a reg hack done with Nero such that it shows me actual burn speed vs just showing me the speed I chose when I began burning. Let me be clearer - my buffer never empties and the laser never has to pause while burning - the system keeps up. I didn't phrase it that way but rather put it into a sort of English that would be easily understood rather than being overly technical. Folks have streamed multiple HD streams from unRAID boxes without stutter, that's probably a more pertinent measurement for most folks but DVD burning is what was asked about.