Arch on Iomega HMNHD Cloud Edition

[solo]

Currently I have two single bay NASes on my desk for testing. I will choose one of them as file- and download-server using ArchArm, and return the other one. It's a "Seagate GoFlex Home 1TB" and the "Iomega Home Media Network Hard Drive Cloud Edition 2TB". I'm tending to the iomega because it has twice the RAM and HD space and i don't need the docking function of the seagate. I figure the 2-core CPU could help on some heavy torrenting as well.

Now my questions:
Anything else to consider, is my valuation completely wrong?
Has anybody Arch already running on an iomega HMNHD?
What of the Pogoplug Pro stuff is usable for me given that the devices us the same SoC?
Could anybody give me some hints on where to start and what to avoid?

I'm a quite experienced Linux user, just not with Arch and this embedded NAS hardware.

Thanks in advance!

[WarheadsSE]

We actually developed our SATA recovery method thanks to the Iomega HMCE.

There are a couple of things to consider here:
- It's still an oxnas board, so support is a little limited in the kernel area.
- The stuff for the Pro wasn't actually designed for the HMCE, but it is possible to use our kernel, but there is no flash on the HMCE at all. Currently, we've loaded ALARM via interrupting uboot.
- It's clocked at 600Mhz, but then it is dual-core and 256MB.

Essentially, if you want first-class device support, don't know how or care to fiddle much, then the GoFlex Home is probably your bet to put ALARM on.

If you're willing to do a little work, to have it do a lot: then go for the HMCE, and xenoxaos and myself will get you up and running without too much headache, but there is no "just run this" script for the HMCE at this time. Heck, you're only the third or fourth person in the community to own one, and 2 of us are oxnas developers.

[solo]

Bad news for the seagate, I guess...

One last general question:
I know you're working on a newer kernel. Can you give me an idea, how much effort this is and how likely it is to be left out in the cold kernelwise too soon? What is to expect from PLX? How much interest is there in the community to support OXNAS*? I know there are no definitive answers. I'm just a little afraid to invest too much work in something that will be dead soon.

Now the first technical ones:
Is it possible to boot from USB-stick? This would avoid the hassle to swap the hdd.
Is it possible to backup the default system without pluging the hdd directly to a PC?
What would be the first steps to get arch running?

Ciao,

solo

[WarheadsSE]

- There is a complete open source package from iomega, but they are also still at 2.6.31.x.
- From what I can tell, PLX hasn't updated their sources at all.
- There are some good pieces of headway available, but the hitch with the pogoplugs the kernel is loaded from nand (because USB is not supported in that uboot) I can't speak directly to the HMCE, but I know that loads from the "ide" aka SATA in their uboot. There is some magic in the stage1 that has to be on the SATA drive's sector 0, and that is where it looks for the bootloader from there.
- You should be able to backup the stock via dd commands, without too much issue, as long as you have a big enough target, you can then compress the hell out of it.
- So far there isn't that much that isn't supported, but I can't say how long that will actually last. With another hand in kernel work, we might actually be able to get up to speed.

To get started, the kernel would best be loaded from disk (possibly only), but uboot access (via serial) would be required.

[solo]

Okay, I ordered a CA-42 cable and downloaded the iomega stuff. I will look into that as soon as time permits. Is it worth the effort to try and get the PLX SDK?

I don't quite understand why serial access to the device is necessary. Isn't it possible to manipulate the HD connected to a PC so that it boots a different kernel and rootfs? Booting from HD is fine so why is there a need to fiddle with the boot procedure?

Ciao,

solo

[WarheadsSE]

You can indeed hook the hard drive up to another machine and setup the correct bits, the hard part is altering the on-disk uboot parameters.

There might be a way to simply do this via the stock image, but I am not certain as I haven't tried it.

I have "hunchback" Pro setup this way:
1 - write track 0 with init & stage1
2 - write sata booting uboot
3 - create partition table via fdisk, setting aside 10MB as partition 1, the rest as partition 2
4 - mkfs.ext3 /dev/sdX2 (I didn't format sdX1, you'll see why in a minute)
5 - dd the kernel uimage (Pro's PCI for me) to /dev/sdX1
6 - update the on-disk uboot to load the kernel from ide0:1
7 - (and I need to improve here) add a command in the uboot process to set the memory to 128 for the Pro

For the HMCE:
There is an actual RTC in that unit, so that helps but means a slightly different configuration. I can also provide you with an overclocking stage1, BUT, it's a much tighter enclosure.

[solo]

I tried to backup the stock hdd with no success so far. I dd'ed the first part of the disk and the first partition to a spare disk, and corrected the GPT partition table. But it doesn't boot. Maybe it has something to do with the complex setup with lvm2 and raid. This sucks and is completely useless on a one bay NAS. It seems, iomega is using this fw on their bigger NASes too. Anyway this setup has nothing to do with the descriptions for the older HMNHD (without "cloud edition") that can be found on the web.

I guess I have to wait until the serial cable arrives to get some error messages. Are there pins for serial on the pogo-pro-board? Seems like on the hmnhd's you have to glue it on solder pads.

I looked into the iomega sources. It contains kernel sources for 2.6.31.14 (this version is running in the stock fw) along with some OX820 patches - nothing special to NAS7820. Is there more available directly from PLX?

Ciao,

solo

[WarheadsSE]

The pins for serial stick off the back of the board. Remove the rear plate (these screws hold the entire thing together, so don't have it tilted off a desk!!), and they are xRGT from the top down (might be xTGR)

Also: NAS7820 = OX820. There was an earlier OX810 that ran a different chipset alignment.

[solo]

I've made some progress in the last days: I've got serial access in place and got it to boot from my spare hd. I was right that it's the raid and lvm setup which makes it stop.

The problem is, it only boots with the first few original-disk-megabytes dd'ed on the spare disk. As soon as i use gdisk to at least correct the partition table it won't boot anymore. Worse, it doesnt seem to find its firmware anymore, so there is absolutely nada on the serial console. dd'ing only the MBR over once again doesn't help.

I'm no expert for EFI and GPT boot mechanisms. Can someone give me a clue what the important bits are in the first section of the hdd to get these devices booted?

I dumped a bootlog here: http://pastebin.com/P5WM9Dsx

Ciao,

solo

[WarheadsSE]

The first bits contains the stage1 bootloader and uboot. I'll try to document my partitioning but I have a 1tb.