Recovering data from a HP Media Vault

I had a customer bring in a drive from a HP Media Vault that had failed (or flaked out or something, we're really not sure yet). It was kind of interesting trying to find data on the drive, so I thought I'd share...

First, the drive obviously didn't have a standard PC partition table.

# fdisk -l /dev/hdi

Disk /dev/hdi: 300.0 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/hdi doesn't contain a valid partition table

I should note that I tried testdisk at this point too, but it didn't find anything. Next, I checked for anything recognizable at the beginning of the disk.

# dd if=/dev/hdi count=8 | strings
Broadcom NAS Version 1.1 MBR Tag
SYSTEM
8+0 records in
8+0 records out
4096 bytes (4.1 kB) copied, 0.00013262 s, 30.9 MB/s

After a little Googling for "broadcom nas", "hp media vault", and a few other things, I figured out there was a reiserfs filesystem on the thing somewhere. (Note: As pointed out in the first comment to this post, there is some great technical documentation on this thing online. Rather than follow it, I chose to cheat and do this the (relatively) easy way.) Google found me this nice document describing the on-disk structure of reiserfs. That's how I figured out that I was looking for a magic string "ReIsEr2Fs" (or "ReIsErFs" for version 1, or "ReIsEr3Fs" for version 3, according to some other search results). I used hexedit to find the offset of the magic string by doing hexedit /dev/hdi, hitting tab, hitting /, then typing in ReIsEr.

2685A020   84 03 00 00  1E 00 00 00  00 00 00 00  00 10 CC 03  06 00 01 00  52 65 49 73  ....................ReIs
2685A038   45 72 32 46  73 00 00 00  03 00 00 00  05 00 B7 08  02 00 00 00  CC A3 00 00  Er2Fs...................

In this case, the magic string was at hex location 2685A034, which means the beginning of the superblock was at 2685A000, or (decimal) 646291456 bytes. The beginning of the superblock is 64k bytes before that, so I set up a loop device there:

# losetup -o $[ 646291456 - 65536 ] /dev/loop0 /dev/hdi
# mkdir /mnt/tmp
# mount -r -t reiserfs /dev/loop0 /mnt/tmp

The files my customer needed were in /mnt/tmp/FileShare/.

Why I suck at business

So anyone who knows me probably knows about the store, but I try not to make a big deal out of it here or in my normal away-from-the-store interaction with people. The fact is, I just don't like mentioning it, for fear that people will think I'm advertising, and I'm only in it for the money. This post is already making me incredibly uncomfortable...

That said, I need some help figuring out some way to advertise some classes I'll be teaching starting in February. Kara and I have invested a lot in the training room in our new store (which makes the local Linux users group meetings much more comfortable), so we have to start making some money on it soon. As it happens, I'm a darn good sysadmin (IMHO), and I like to talk, so teaching is a natural thing for me. ;-)

The classes I'll be teaching are all Linux system administration-related. Half of them are LPI Linux certification classes (on account of the O'Reilly book on the subject I helped write). There's a Google Calendar with dates, but no class descriptions yet. (Details available on request, but I obviously need to get them posted somewhere...)

So I need to figure out a way to get the word out, preferably to the St. Louis area (and the midwest in general, I suppose) that a) doesn't cost a ton of money (because that's all tied up in the new shop), b) doesn't make me feel like a total weasel, and c) doesn't make the intended audience think I'm a total weasel. Suggestions (like, what advertising do you actually pay any attention to and maybe trust a little) would be most appreciated.

Oh, since I'm talking about work, and in case my lovely and talented wife reads this, I have to point out for the record that she owns and runs the business. (In addition to being extremely averse to "sales", I also happen to be horrible with money. On the other hand, she happens to be good at that and more. :-)

Hard drives suck

In my day job, we go through a lot of hard drives. It seems now that no matter how good a drive manufacturer is, drives still show up DOA, die early, die not-so-early, etc. This is the reason I like Seagate so much. While I fully expect their drives to start dying naturally at 18 months or so (they don't always, but that's when I really start keeping an eye on them), at least with their 5-year warranty I know I can get replacement drives without spending a lot of money constantly.

Anyway, a while back I got rather tired of replacing drives that were DOA or after less than 30 days of service, so I figured out that burning them in with a combination of SMART self tests and badblocks seemed to weed out the early failures rather well. I wrote this script to run those tests for me. All it needs is smartctl and badblocks (which are probably available on most live Linux CDs, but definitely on Fedora and Knoppix). It will work on any IDE or SATA drive. With a little work, it could probably handle SCSI drives, ATA drives on 3ware controllers, etc.

cpanspec 1.74

I released cpanspec 1.74 this morning. There's some information about it on the Fedora wiki, but the short version is that cpanspec generates spec files (or, optionally, rpms) for Perl packages on CPAN. As an example, you could build a source rpm for String::Random like this:

$ cpanspec -v -s String::Random
Updating /home/steve/.cpan/sources/modules/02packages.details.txt.gz...
Fetching /home/steve/.cpan/sources/modules/02packages.details.txt.gz from http://www.cpan.org/modules/02packages.details.txt.gz...
Fetching String-Random-0.22.tar.gz from http://www.cpan.org/authors/id/S/ST/STEVE/String-Random-0.22.tar.gz...
Trying to fetch description from String-Random-0.22/lib/String/Random.pm...
Writing perl-String-Random.spec...
Building source rpm from perl-String-Random.spec
Wrote: /home/steve/src/fedora/rpms/cpanspec/devel/tmp/perl-String-Random-0.22-1.fc7.src.rpm

Unlike most other automated (or semi-automated) solutions for building spec files for Perl modules, cpanspec actually gets the Summary, License, URL, description, and dependencies (if available) from the CPAN metadata and other sources. In many cases, packages generated with cpanspec are completely done and ready to use (or submit for package review).

Obviously there are a few things cpanspec doesn't handle well. See BUGS and TODO. Patches always welcome. :-)

Overdue update

I'm leaving for the Ohio LinuxFest in a few hours, so I thought this would be a good time to give a quick update.

• The store is coming together, slowly. My KVM head units finally showed up, and now that I've seen them, I've reconsidered how I want to cable everything a bit. (One of these years, I'll have to write up what we're doing, maybe with some pictures...) My switches in the front of the store are too loud, so I have to find a way to quiet them down before I can use them. The lighting in the front of the store still isn't right. Our training room furniture still needs to be assembled. We still have a lot of stuff that needs to be unpacked. There's probably more that I'm forgetting, but at least we are making progress...
• We've had some drama with our employees. We had one person quit after Kara and I went over some complaints. (At least we won't have to worry about those issues any more.) One employee is moving away to go back to school. Another gave us notice so he could take another job, but I think we convinced him to stay. And then we have a new guy starting next week, which means we get to train him for a while...
  
• I'm very slowly easing back into doing Fedora work, mostly just to take a break from all of the above. Hopefully I'll get a chance to try out 7.91 over the weekend. (I'm burning a copy to take with me now.)

With all this stuff going on, I'm not thrilled about leaving for a few days, but I probably need the break.

Moving sucks

Construction on our new store is done (finally), so we're moving in now, just a little later than originally intended. We're going to shut down this weekend so we can get everything in the new store set up. Hopefully we'll be mostly functional on Tuesday (2007-09-04, after the Labor Day holiday), but I have a feeling it will be a week or two before things settle down to something like normal...

On buying laptops

I posted the following in the LinkedIn Answers section earlier today while I was taking a little break. Maybe it will be useful to someone...

Since we work on laptops that are both in and out of warranty at my job, my first concern is usually how easy a laptop is to work on.

With that in mind, whatever you do, don't buy Dell. Dell's primary business goals appear to a) lock people in, and b) make sure systems self-destruct in a relatively short time so that the customer buys another computer.

Avoid any laptop that has a power cord that doesn't have a normal round plug with the opening for a center pin. That rules out Dell, half the Toshiba laptops, and various others. One of the most common repairs on a laptop is a broken power jack, and the round ones tend to be easier to fix. Plus replacement power adapters tend to be easier to find (and cheaper).

For most people, Lenovo laptops (especially the Thinkpads) would be my first choice... They're reasonably priced, solid, and fairly easy to work on. (I thought that even before our shop was set up as an authorized service center, although that certainly helps with our customers.) For some of the higher-end models, especially gaming laptops, we usually recommend MSI and Asus. If you want really small and light, Averatec usually has some really nice models, although be sure to shop around a bit if you want to go that route. Often you can get an identical laptop from MSI or another company either with better specs or a bit cheaper.

The one exception to my normal rules is the MacBooks. They have a weird power adapter, they aren't terribly easy to repair, and it looks like most of the engineering effort on them went to making them pretty, not providing good airflow, etc. Still, they are nice to look at, they are light, and they're pleasant to use. Just be prepared for them to be a bit more disposable than your average laptop.

A lot of the bigger name-brand laptops (Lenovo, Acer, etc.) will let you buy an extended warranty (Acer will go to 3 years, but I think Lenovo will go up to 5) that covers accidental damage. If you travel a lot, or you are at all worried about accidents, it is well worth the extra money. Not to mention the odds of needing a warranty in 3-5 years is much higher than in the first year.

Oh, and one last thing... Make sure you have good backups of anything on your laptop. Laptop hard drives get much more abuse than desktop drives, so they tend to fail faster than desktop drives. Unfortunately, they tend to be a lot harder to recover data from than desktop drives too.