Archive for November, 2006

SftpDrive Rules »

I support a number of developers. These developers all have Windows desktops, but need to edit their code which resides on UNIX hosts (AIX, Solaris, and Linux).

I love Samba, but not if it’s installed on 300 UNIX hosts. It’s another software package that needs to be configured, firewalled, monitored, patched, and maintained. The permission model for Samba is somewhat orthogonal to the permission model for UNIX hosts, too, so my tools for handling user accounts won’t work.

My developers want to edit their code with local GUI text editors. Getting them to use X11, or even text editors via SecureCRT is not a good solution, mainly because they resist. I’m cool with that. I know what tools I’m most productive with, and take the same stance when someone tells me otherwise.

Not a week goes by where some developer does not lament the lack of Samba, though. This has been happening for years. I have mental callouses now for the complaints. We had looked for other alternatives about two years ago and found nothing that wasn’t more complex than just using SecureFX/scp. Yesterday, though, one of our junior admins was lamenting the lack of Samba, too, and with a little searching found SftpDrive. Like their web site says, it just works.

Hell yeah. Problem solved. Guess what our desktop support guys are going to be deploying next week…

Something Is Fishy »

“I see they’ve got you doing everything around here now.”

I was opening the janitor’s closet outside of my office. They have a nice sink in there that makes cleaning our fish tanks easier. My friend Eric was walking past as I was unpacking the closet.

“Yeah. I guess I shouldn’t have been a smartass to my boss,” I said with a grin.

“But seriously, why are you in the janitor’s closet?”

“It makes maintaining the fish tank easier.”

“Oooh, you guys have a fish tank?”

“Yeah, come here and take a look.”

Our cube farm has two tanks. One is in the middle, just as you walk in the door. It’s 55 gallons and has orange platys, green tiger barbs, silvery red-eyed tetras, blue neons, orange and black clown loaches, brown algae eaters, silver hatchet fish, and a twelve inch black plecostomus. It sits right next to our conference table, and during meetings people sit and stare at it. It’s nice like that. If I want to get my mind off of whatever I’m working on I can go watch the fish for a while.

Or, in my case, clean the fish. The tank was my idea, and I am responsible for it. Which is hard when I’m gone for a week, and something goes wrong.

“Should the water be green like that?” asks Eric, as I suck-start a siphon to change some of it. My advanced siphon starting techniques are overshadowed by the pastel green water pouring from the end.

“No…” I reply. “That isn’t healthy.”

The problem was that we messed with the tank last Thursday. I was leaving on vacation on Friday, and we cleaned the filters, changed water, and vacuumed the tank pretty heavily. We also changed the complement of the fish. The other tank in our office is in my cube, a ten gallon glass rectangle serving as hospital, isolation area, and snail breeding ground. We’d moved a number of fish around between the tanks.

Many of the same strategies that apply to large scale systems management apply to fish tank management, too. First, you shouldn’t make shotgun changes. One change at a time, and then let the ecosystem stabilize. Second, you should not make changes right before you’re leaving on vacation. You won’t be around to tweak things if the ecosystem doesn’t stabilize the way you’d like, and you leave it up to others who may not be on the same page as you to do emergency work.

This time the tweaks were needed to unclog the filters. There are three types of filtration in a tank: mechanical, chemical, and biological. Mechanical just removes debris. Chemical neutralizes harmful chemicals with other chemicals. Biological neutralizes chemicals via bacteria. Bacteria eats the fish waste. Plants eat the bacterial waste. All that’s left gets changed in weekly partial water changes.

Except when the filters get clogged.

And I’m on vacation.

And now I have cost the lives of three fish, because I didn’t listen to what I tell the rest of my system administration team. Sure, I tell them about computers, not fish tanks, but it’s the same deal.

Grrrr. Welcome back from vacation, Bob.

Dell PERC 5/i Not Caching »

I noticed this morning that the RAID containers on my new Dell PowerEdge x9xx servers don’t have their caching options enabled. Now, I understand that write caching is potentially risky, and I understand why Dell ships the PERC 5/i controllers without write caching. However, no read caching? That doesn’t make much sense.

While I was mucking around I did some benchmarking of the controllers with different cache settings. I used Red Hat Enterprise Linux 4 Update 4, running on a Dell PowerEdge 2950 with six 146 GB 10K SAS disks. The filesystem is a 20 GB ext3 volume created in LVM, mounted with data=writeback. I used bonnie++ to generate load, which for that tool means sequential writes and reads. Each test was run five times and averaged, then the machine was rebooted to change the controller settings. While the machine was in multiuser mode (runlevel 3) I was alone on it, and it was not doing anything but my testing.

Note: if you have a good tool to test random I/O please leave me a comment with the link. The most promising tool I could find was POSTmark, from NetApp, but it looks like they removed that from their site. I could write something, too, but I didn’t have time here.

Anyhow, the results are fairly obvious. The graph is:

PERC 5/i Options vs. Performance

The conclusion, at least for sequential reads and writes, is to turn your cache on for maximum performance. No surprises there. :-)

Update: The array was configured as RAID 5, across all six disks.

My Excel Wish List »

Say what you will of me, I love Microsoft Excel. I don’t think my life as a system administrator would be as easy without it. Basically, I love it for Autofill in combination with it’s text functions, and also for charting.

There are three things I’d love to see Excel do better, in these regards:

  1. I wish Autofill recognized IP addresses. It will increment them now as numbers, but when I get to x.y.z.256 I have to start over. Not a huge deal, just would be nice to see it say “Hey, this is an IP” and do x.y.z+1.0 or something.
  2. I wish Excel in general, and Autofill in particular, could handle hexadecimal numbers. And along with #1, IPv6 addresses would be cool.
  3. I wish the charts had color scheme options that accommodated people with color blindness. 25% of the people in my group have some form of color blindness. I’d love a series of checkboxes where I could indicate the types of color blindness I’m dealing with (total color blindness, red-green, or blue-yellow) and have it choose better colors.

That’s all. Maybe I’ll see if there’s a way to submit these directly to Microsoft.

Update: I love blogs… Mark Bower has the link in a post, first hit in Google.

Sunlight »

“Publicity is justly commended as a remedy for social and industrial diseases. Sunlight is said to be the best of disinfectants; electric light the most efficient policeman.” - Louis D. Brandeis

OMFG, Commercials Are Sooo Dumb »

I don’t know what it is tonight, but I find myself watching television commercials more than usual, now that I’ve commented on other premature, white supremacist toilet brush commercials. The last commercial I noticed in the background was one from Glade. The final statement in the commercial is:

“…and when the oil runs out the candle goes out.”

Really? WOW! Maybe there’s a type of combustion that doesn’t require fuel. Which makes me think that if there is and the folks at Glade know about it they have the energy market cornered. Maybe they aren’t releasing it because it hasn’t passed various government safety tests. It’d suck trying to put out a fire caused by fuel-less combustion. Maybe it’s like a combustive version of Ice Nine, making oxygen scarce.

(sorry, I’m just in one of those moods)

links for 2006-11-13 »

Christmas Already? And some KONE racism? »

I’m sitting on my couch catching up on my reading, and I have the television on in the background for noise. And…

…a Christmas Tanqueray advertisement just played. I looked up because I heard the sweet sounds of “Deck the Halls.”

WTF? We have — count them — eleven whole days until *Thanksgiving*.

Every year we gain a couple more days of the Christmas season. This isn’t a bah-humbug sort of attitude. Similar to locking operations in software or XML tags, I like my holidays atomic. :-)

I was stunned for a second following the Tanqueray ad, and ended up watching an advertisement for a new designer handheld vacuum, KONE, from Dirt Devil. “It’s beautiful enough to stay on display,” according to their web site. For me, though, it looks strikingly like my toilet brush holder.

“Kolorful, Konvenient, and Klean,” according to their web site, which shows the white model… hmm. What’s with the three K’s, anyhow? Don’t marketing people worry about this stuff anymore?

And no, this isn’t a PayPerPost ad, it’s just me pissed off at Tanqueray and Dirt Devil.

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