RAID on SheevaPlug

[A_W]

Hi, everybody!

I bought a Plug to use as a server (mainly file server) for my home network.

Concidering the frequency of drive failures, I am now thinking about making a RAID-5 or -6 array; they give full protection against drive failure at the cost of one or two extra harddrives respectively.

RAID is now supported right in the linux kernel, and there are tools that e.g. lets you add new discs to an array without having to do a lot of terminal work, as well as using USB discs, so that should all be fine.

The thing is, that RAID-5 and -6 can take a lot of effort on the part of the computer running the array, since there is a lot of read/write manouvers and parity-computing.

What I am wondering, is therefore: Does anyone have any experience of running RAID on av Plug?

Any and all suggestions are welcome.

[jlpoole]

I just had a Seagate 1.5 TB fail on me, I had my /var and /usr mapped to it so I'm hosed.  My setup had been working flawlessly and I really put it to the test compiling some monstrous stuff.

Now I'm looking for a RAID solution.

Drobo looked possible, but as I read the reviews on Amazon, there are too many complaints, some serious insofar as files are just missing without notice and Drobo simply reboots.  Looks like Drobo is not a good candidate.

So the issue becomes do I find a SheevaPlug => USB => RAID solution, or can I do a RAID within my operating system, Gentoo, with mounted USB drives.

No answer yet, just thought I'd post my current thoughts.

[fragfutter]

don't run software raids on USB disks.

[pingtoo]

don't run software raids on USB disks.

Agree. In the past I have setup a PC with USB raid (mirror) it always hung at some later time after some heavy I/O.

[jlpoole]

don't run software raids on USB disks.

I am taking this to mean that you do not recommend RAID =>USB=>disks. 

Would you have any suggestions for a USB=>RAID=>disks solution, which I guess is a stand-alone hardware solution where the hardware RAID configured drives are exposed to the USB port?  This is the approach Drobo takes.

[Blüto]

1. I'm using a Sans Digital MobileSTOR MS2UTN+B dual-bay USB/eSATA RAID enclosure ($99) with a pair of WD10EADS 1 terabyte "green" drives in a RAID 1 array, and I've been very happy with it. The unit contains a Silicon Image RAID controller which handles the overhead of mirroring writes and striping reads. (See a video review of the MS2UT+B -- the UTN's big brother with an LCD display, though the unit can also be controlled with an x86 driver for Windows, Mac and Linux):

http://www.youtube.com/watch?v=l5kPXUOgpbk

2. YMMV, but I'd never trust a software RAID solution via USB. The interface is just too slow (25 MB/s tops and vulnerable to being crippled by simultaneous I/O streams). The only thing I don't like about my current setup is the poor performance of USB, so my main motivation for ordering the GuruPlug Server Plus is to gain access to an eSATA port which will allow me to move I/O intensive tasks (like MythTV) to the plug without bringing the system to its knees.

[pingtoo]

I think hardware raid is the way to go if your main concern is reliability. however raid is not substitution for backup(availability) since you are on Gentoo I recommend investigation the stage4 procedure if you have not already do so.