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GRAFFITI -- August 21, 2006 thru August 27, 2006>> Link to the Current Week <<Last Week << Mon Tues Wed Thu Fri Sat Sun >> Next Week Welcome to Orb Graffiti, a place for me to write daily about life and computers. Contrary to popular belief, the two are not interchangeable. About eMail - I publish email sometimes. If you send me an email and you want privacy or anonymity, please say so clearly at the beginning of your message. |
 
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August 21, 2006
1741 - Good afternoon. Here's the difference between a fast ethernet adapter and a gigabit adapter in transferring two identically sized very large files via scp:
bilbrey@vimes:~/testfiles$ time scp AVeryLargeFile.wtf vroomfondel:. AVeryLargeFile.wtf 100% 4465MB 10.9MB/s 06:48 real 6m48.435s user 2m3.856s sys 1m8.244s bilbrey@vimes:~/testfiles$ time scp AnotherLargeFile.wtf vroomfondel:. AnotherLargeFile.wtf 100% 4465MB 16.5MB/s 04:30 real 4m30.671s user 1m8.436s sys 0m49.231s
So, I've removed the network from contention as the bottleneck. In this case, I'd have to suspect that the decryption/decompression at the receiving end, which is only an Intel(R) Celeron(R) CPU 2.53GHz, as compared to the AMD Athlon(tm) 64 X2 Dual Core Processor 4400+ on my workstation. The cache size is the key factor there - it's a factor of 4. I'll do another test later to see what it's like when using plain rsync, without tunnelling or compression. But now, to feed the dogs and pay the bills...
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August 22, 2006
1141 - Good morning. I observe that some high-level slaughter is taking place at AOL as a result of the search results scandal. Three heads have rolled so far, and that's probably not the end of it. Personally, anyone who has an expectation of privacy in those circumstances is likely deeply deluded ... but it's a nice goal to have (privacy, that is).
If you haven't tried out Google Writely yet, then sign up and give it a try. Please note that I gave you a secured link there. Always assume that when you're doing stuff that isn't just reading or regular news/research stuff, that you should be using a secured connection. Writely is an Ajax-powered online editor that lets you share documents among registered users. I've only played with it a little bit, there might be some real use when collaboration is needed. And the price sure is right. Previously it was an invitation-only service, while the infrastructure of the little company that Google bought was ramped up to handle greater loads. Now you can sign up and start using it now. It certainly doesn't seem to be a front-runner for my primary word processor, but as an available-anywhere for my toolbox ... it's pretty interesting.
Okay, time to get back to debugging Red Hat init scripts. Have a great day!
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August 23, 2006
0824 - Good morning. Today, the fourth named storm of the hurricane season, Debby, is about 350 miles off the coast of Africa. It may become a hurricane in a few days, but also isn't likely to threaten landfall, according to forecasters. It's been quiet so far ... this year. On this date last year, the eleventh named storm of the season was one day away from achieving tropical storm status, with winds just under 45 miles an hour. On August 28, the storm hit Category 5. One could say "fortunately", Katrina weakened to a Category 3 storm before slamming into the Gulf Coast. It continues to blow my mind that they're rebuilding New Orleans in place. You know it'll happen again. I know it'll happen again. WTF?
Time to take a few days off. I'm stretching the weekend by three days this way, and two days on the backend. On the list first is a two-fold task: Bringing our fishing gear up to snuff, then going fishing. The fishing gear hasn't been used since we lived in California. So the line is old, brittle. Any bottled baits are toast. The downside is that I slept really badly last night, and coffee is only making a tiny dent in the lethargy. We'll see how the day goes. Ciao!
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August 24, 2006
0637 - Good morning. The gear is in the truck, we'll head out in a few minutes to go fishing. I got all new line, sharpened all the knives, threw out the old baits ... we'll pick up a short-term license when we stop, and depending on what's biting, baits or lures to suit. Oh, I did get the rsync test done yesterday, and saved the data to post...
bilbrey@vimes:~/testfiles$ time rsync -av AVeryLargeFile.wtf vroomfondel::bilbrey/. building file list ... done AVeryLargeFile.wtf sent 4681990359 bytes received 38 bytes 38854692.09 bytes/sec total size is 4681418752 speedup is 1.00 real 2m0.284s user 0m25.710s sys 0m37.518s
So, from nearly 7 minutes to transfer a large file, encrypted, over a Fast Ethernet link, to 4:30 for an equivalently sized file transferred encrypted over a gigabit link, down to 2 minutes when we take encryption out of the mix. Can it be faster still? Perhaps netcat has less overhead than rsync? So I setup a listener on Vroomfondel, the home server: nc -lp 3333 > mybigfile2 ... then I started a timed run from Vimes, my workstation.
bilbrey@vimes:~/testfiles$ time cat AnotherLargeFile.wtf | nc -w 1 vroomfondel 3333 real 2m8.834s user 0m0.500s sys 1m23.953s
Interesting. I didn't expect rsync to beat out netcat. In a quick Google search, I can't find any related data to back up this factoid. Of course, the difference is miniscule, in real terms. With rsync, the 298 Mb/s is not even a third of the capacity of the network bandwidth. So what's the issue now? More testing another time, when I have another system with native gigabit networking, instead of an add-in PCI card. I could have gotten a PCIe gigabit adapter for 60 bucks more than I paid for the current card in Vroomfondel, but that didn't seem to make much sense. I've gotten better than 3x transfer improvement. With nightly backups from the workstations to the server, that's probably good enough.
Now, time to go fishing. Have a great day!
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August 25, 2006
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August 26, 2006
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August 27, 2006
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Visit the rest of the DAYNOTES GANG, a collection of bright minds and sharp wits. Really, I don't know why they tolerate me <grin>. My personal inspiration for these pages is Dr. Jerry Pournelle. I am also indebted to Bob Thompson and Tom Syroid for their patience, guidance and feedback. Of course, I am sustained by and beholden to my lovely wife, Marcia. You can find her online too, at http://www.dutchgirl.net/. Thanks for dropping by.
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