Monday, July 29, 2013

Un-super slo-mo

As last week was drawing to a close, I was perturbed to note that certain factors out of my control seemed to be getting worse and worse. I had gotten to the point where I only had one year’s worth of files to copy, a single directory, so I started the process and let it run. It was not running terribly fast, but that was about what I expected. I have never shied away from confessing that I am not really a network guy, nor am I fully initiated in the higher sysadmin mysteries, so I don’t really know with exact certitude what factors dictate or influence how quickly data can move from point A to point B. I know that there are physical limits to the carrying capacity of the network connections, and I know the overall traffic has to be managed somehow and there must be pre-programmed rules that determine which actions get bandwidth priority and so on … it’s possible that the network resources are capable of automatically evaluating the size of a job as requested and can shunt the job into the slowlane based on enormity, leaving lots of high-speed capacity for smaller jobs which shouldn’t have to wait behind the big slow behemoth. I can appreciate the wisdom of that kind of procedural resource management. My jobs can run overnight, it’s all the same to me as long as it gets done.

So at its pokey little rate of transfer my final copy job ran all day Thursday and I left it to run overnight. It got a little further, but not as much further as I had hoped, and I noticed on Friday morning that the transfer rate was even slower than it had been when the job started. And as the last workday of the week elapsed the rate continued to fall, so the job had not yet completed when I left. But surely everything would finish up over the weekend, right?

Well, not if my task was locked into some kind of hellish inverse Zeno’s paradox of data transmission, where the first half of the batch of files transfers at 1 MB/sec, and then the first half of what’s left transfers at 100 KB/sec and takes ten times longer, and then the first half of that remainder transfers at 10 KB/sec and takes an order of magnitude longer, and so on and so on until my workstation actually begins approaching the heat death of the universe.

The tortoise may in fact be moving backwards in time at this point.

And something like that did in fact seem to be the case this morning when I arrived to find that the task was still far from done and was crawling along at some laughable pace measured in bytes per second. BYTES. I have gigs of data (lemme do the math for you, = literally billions of bytes) to move and it is ambling along the cables and over the routers like it has nowhere particular to go and all day and then some to get there.

This too shall pass, this too shall pass. If the network is going to keep slowing my job down the longer it takes, which is only going to make the job take longer, in a vicious feedback loop, then I will find a way to work around that, break the job up, trick the network into letting me at least use the slow lane instead of pushing me into the ditch on the side of the road. But man oh man. I’ve been saying that when this project is over I can finally a take a day of paid time off and catch up on some non-work responsibilities I’ve been neglecting, but at this point I think I may have to take a day or two to just drink heavily, sleep it off and blot out all memories of the experience.

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