December 2012 Archives

How multi-disk failures happen


Having seen this failure mode happen a couple times now, it's time to share. Yes, Virgil, multi-disk failures DO happen during RAID rebuilds. I have pictures, so it MUST be true!

First, let's take a group of disks.

Eight, 2TB drives in a 7-disk RAID5 set. With hot-spare! 10.92TB of usable space! Not going to fill that in a hurry.

On this array we have defined several Volumes.
15 of them, in fact. One of which is two volumes merged together at the OS level (vols 2 & 3). That happens.

It just so happens that the particular use-case for this array is somewhat sequential. Most of the data stored on this bad boy is actually archival. The vasty majority of I/O is performed against the newest volume, with the older ones just sitting there for reference. Right now, with Vol 15 being the newest, Vol 1 hasn't had anything done to it in a couple of years.

That said, time is not kind to hard-drives.

What's involved in eDiscovery?

Having spent last week at Lisa12 I ended up having to describe what my company does to people who ask what I do. Few people outside of the Legal industry know what all is involved. The part of the industry where Sysadmins live are only familiar with one stage of it, if they're familiar with any of it at all: collections.

If you drop "ediscovery flowchart" into your search-engine of choice you'll get a wide selection of graphics. To save load, I'll give it in outline form:

  1. Records Management
  2. Identification
  3. Preservation
  4. Collection
  5. Processing
    • Early Case Assessment
    • Review
  6. Production
  7. Presentation

Now to go into a bit more detail.

LISA12 so far

I'm on the blog team, so you'll see some familiar names over here.

This is my first trip to the West Coast after moving east, so it's the first time I've had three time-zones this direction to get used to. It's... tricky. Getting to 11pm and being ded is a new experience, as is waking up at 5am wide awake and ready to go. I'll get used to it, and then go the hard direction when I got home on Saturday.

The sessions are interesting, look for my posts on the Usenix blog for that.

The hotel is nice but is kinda isolated. Well, a lot isolated. The only food options are the Hotel places (expensive) other Hotel places, and three high end places. No quick food, and the lack of fridges in the room make hunting up a grocery store not as effective as it could be. So, food is kinda expensive.

The views are spectacular though.

My company has one of our remote workers living in this town so we had dinner Sunday night. It was great! San Diego's Little Italy has many places to eat, and the spot we landed in was a Jazz Bar with a pretty good band playing and excellent food. Perfect!

Today I have How To Succeed In Business As A Sysadmin (a.k.a. A sysadmin's guide to navigating the business world) and Documentation Techniques for Sysadmins. Tomorrow the Technical Sessions start and I'll be a lot busier blogging for that.

Heading to LISA 2012

I will be in San Diego next week for LISA. First I've I've been there, and right now it looks like the highs will be in the 70's for the week. I think I can live with that. Hopefully the conference hotel isn't refrigerated to the point that I'll need long pants and sleeves to avoid freezing.

Not that I'll have much time for enjoying the weather. I'm one of the Official Bloggers so I'll be writing my way through the conference. The LISA Reception Thursday night is onna boat, and people will be dressing spiffy (or as spiffy as datacenter dragons get).

Oh, and learning and stuff. I'll be there in time for the Saturday AM sessions, so I'm getting all of it. It's going to be a long week, and it's a very good thing it's my job to take lots of notes. I'ma gonna need it the week afterwards when I have to communicate it all to my coworkers.

A very special interview

Today I have a very special interview. I have with me Steve, who is responsible for North Pole IT operations. As you can imagine, he is rather busy this time of year so I'm glad he had a chance to talk with me.

sysadmin1138: Thanks again for talking with me. But first, the question on all of our minds, how in the heck did you LAND that job?

Steve: I just sort of fell into it. I was on the Admunsen-Scott over-winter team for 2007 and 2008. You know, the South Pole station? It was the day after the Winter Solstice in 2008, which is June 22nd for you northern-hemisphere people, recovering from a massive hangover from the party the night before when a Christmas Elf showed up in my room.

sysadmin1138: That must have been a big shock.

Steve: You have no idea. He was about four feet tall, big, pointy ears, green felt hat and jacket, with yellow pants. You'd scream too if you saw that staring at you when you woke up. The elf assured me I was quite sober, a fact I was painfully aware of at that point. He passed me a mug of egg-nog and told me what he was doing there. The Big Man liked what I was doing down here, was looking to modernize his operation some, and would I be willing to be part of it? What with me already familiar with arctic IT and all.

Turns out that nog was spiked, which helped with the hangover a bit, and helped settle my nerves. Yes, they really were looking for a systems engineer. They already had an IT plant of sorts but the old guy had expressed a desire to retire and see more of his grandkids. This was just too loony for reality so I said, "Pfft, sure." He companionably clapped me on the back, shook my hand, and left.

It was only the next day when the nog-mug was still there when I got up that I got the inkling that perhaps, maybe, that elf was actually in my room and not just in a room in my head.

It turns out that mug shouldn't have gone in the dish-washer. That was the period to my suspicion that I'd dreamed the whole thing. I mean really, who dreams up breaking a mug in a dish-washer?

sysadmin1138: I've dreamed up UPS alarms, but not mugs-in-the-dishwasher I have to admit.