27 July 2010

time to move along for my home raid.

Back in January I wrote:

Now hopefully by then, Drobo will have a newer droboshare that's compatible with the bigger arrays like the S... and connects via eSATA or FW800. And hopefully they also have a larger enclosure (6-8 drives) that doesn't have all the extra enterprise features... or has the droboshare built in.

Drobo recently wrote:

You told us what you wanted, and we listened.

Wow. I'll say they did.

That's almost a perfect solution to my home network storage needs. Close enough that I just bought one with 3x 2TB SATA-II drives. (plus it will inherit a 4th from the current raid that replaced the last dead IDE drive.)

What got me moving? Another dead IDE drive. Plus the root file system's USB key is dying... which seems to be killing the userspace parts of the NFS subsystem... which is killing file access for the clients that depend on that storage. (Namely my desktop, Cory's desktop and my laptop.)

Wait, "Root filesystem's USB Key"?

Yeah. This box was built many years ago, when I was an embedded linux hacker at work. The setup is pretty sweet, if I do say so myself. The box boots from two USB keys, one is 128M and the bios sees it as a USB Floppy (so it's bootable), the other is 4G USB key that the bios doesn't see as bootable, but it will recognize as a USB HardDrive. This means that when grub (on the smaller /boot key's bootsector) comes on line, it can access the larger / key via basic bios calls. That key contains the rootfs which is mounted readonly. (The rootfs does have a small number of directories that symlink out to the raid array for read-write storage... /tmp, /var, /home, etc... but generally speaking, the *OS* runs out of a read only image. But the kernel build date is a shade over 4 years ago... and it wasn't a "current" kernel then... I remember rebuilding it by hand because I updated some stuff in the distro which pulled in a glibc update which wanted a kernel update and I refused to upgrade to a new version when I could just patch the compatibility into the one I had working with all my mythtv hardware at the time. (forums said I'd be broken if I upgraded... I didn't wanna risk it.) The bulk of the distro is even older... just a few targeted updates trying to get various things working over time. Many of which never did.

The hardware is pretty fly too... It's a standard "server" tower, with 6x 5.25" bays on the top half of the case. Those bays hold the 6 drives of my raid array, with a custom mounting for a thermally controlled pair of 120mm fans. Great cooling with very little noise. The rest of the system was spec'd out similarly.... the cpu for example is a mobile athlon6. Why mobile? because it gives me the ability to dynamically clock the processor down to 800Mhz for power savings and more importantly to make it quieter. Once upon a time, this box also had my mythtv tuners and a display board and optical digital audio out. The tuner had mpeg encoding hardware, and the display had mpeg decode hardware... so I could be recording one show and watching another and the CPU could remain at 800Mhz with a low load level. Even with software raid. It would suck to have that ability killed by a loud system. :)

I'll probably add the case and system board for that box to the pile of stuff I need to eBay.

So enter Drobo, and their droboApps. Some of the things I was trying to make work, are available as apps already. Firefly and fuppes for example. Other things are just built right in... like AFP. It will be nice to move off of NFS as the main access method here, since this is largely a Mac household now. It looks like I'll be able to migrate the few things I have left on the server to the Drobo with just a little bit of coding. (At least one of them might make for a good DroboApp if I do a little polish on it... will have to see how well it works on the Drobo FS. I worry that it might choke on the compute requirements... I had to spin the processor up to 1600Mhz when this job ran nightly. Or the pre-reqs.) Now I just have to wait patiently for it to arrive, so I have my serial number and can go create my account on their developer site to get a look at the SDK and see what my options are.


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