Magic Dragon Theatre (Dec 21 2007)


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Profile Matt Lebofsky
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Message 693470 - Posted: 21 Dec 2007, 18:27:07 UTC

Happy Holidays! As a present thumper (our main science database) crashed for no reason this morning. Not even the service processor was responding. I wasn't planning on coming to the lab today but here I am. Long story short, Jeff/Bob/I have no idea why it crashed - I found it powered down (but with standby power on). I powered it up no problem. Some drives are resyncing, but there's no sign that any drives died. In fact, every service on it is coming up just fine, including informix. Also no signs of high temperatures, or other hardware failures. Well, jeez.

While the main disks are syncing up I'll leave the assimilators/splitters off. We may run out of work, but hopefully not for too long.

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Message 693493 - Posted: 21 Dec 2007, 19:24:17 UTC - in response to Message 693470.

Hmmm...that's worth checking the logs on that server. Something must have shut it down....UPS monitoring, someone hitting the power button, root login just before shutdown. Was it a clean shutdown? Or did the power fail and cause disk checks upon restart? I don't like it when my servers shutdown without my approval.

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Message 693498 - Posted: 21 Dec 2007, 19:47:37 UTC - in response to Message 693494.
Last modified: 21 Dec 2007, 19:53:32 UTC

The janitor hit the power button with the butt of his broom.......

Or in the case of our shop, you could have left off...
of his broom...


(We don't call Don 'old wide load' for nothing ya know)

And this time of year, mysterious superfluous server reboots are usually caused by hoards of untamed underpants gnomes.

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Message 693598 - Posted: 22 Dec 2007, 1:12:19 UTC



Thanks for the Postin' Matt - hope ya find the culprit ;)

hmmm . . . Todd Rundgren eh - quite the 'eclectic' collector there Matt

Utopia: "Magic Dragon Theatre" - Album: Ra 1975


Look at all the advertising
Some kind of show, come if you're going
Patronize the magic dragon
Walk through the door, kiss off your boredom
Tuning up the orchestra, bringing down the ceiling lights
All at once the curtain goes up
Now it begins, strike up the band
Bring on the dancing girl's and the freak parade
Look to your right where a gentleman sat
There sits a monkey in a tall silk hat
The lady on the left is now a pumpkin pie
That's when you notice that your chair is flying
High in the sky out over the sea
But don't wonder why, where else could you be but

Where anything can happen,
Down at the magic dragon theatre
More than you can imagine,
Down at the magic dragon theatre
(come to the magic dragon)
Do you fancy melodrama?
Tragedy's mask, yours for the asking
Madness a la magic dragon

Who could that be at this time of night?
I'm sure we weren't followed dr. klang
Wait, pull down your knickers, he's going to hit us
Here goes your cue, don't blow your line
Dam, danger! I'm gonna go out there and get, get, get ...

All of a sudden there's a flash of light
Stars begin appearing in a moonlit night
Your vision of reality has gone awry
That's when you notice that your mind is flying
High in the sky out over the sea
But don't wonder why, where else could you be but



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Richard Haselgrove
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Message 693709 - Posted: 22 Dec 2007, 10:31:28 UTC - in response to Message 693470.
Last modified: 22 Dec 2007, 10:34:40 UTC

We may run out of work, but hopefully not for too long.

- Matt

Pity the next tape in the queue came from an Arecibo ALFALFA observing day.

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Message 693783 - Posted: 22 Dec 2007, 19:23:01 UTC - in response to Message 693709.

We may run out of work, but hopefully not for too long.

- Matt

Pity the next tape in the queue came from an Arecibo ALFALFA observing day.

ALFALFA is drift scan, the 100p2 scan done on Dec. 1 2006 was at 24.333366 degrees declination so should be around AR 0.40x. The pity is they only had a 3 hour observation period that day and so far it appears the other observations were at high slew rates.
Joe

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Message 693787 - Posted: 22 Dec 2007, 20:25:09 UTC - in response to Message 693783.
Last modified: 22 Dec 2007, 20:33:28 UTC

We may run out of work, but hopefully not for too long.

- Matt

Pity the next tape in the queue came from an Arecibo ALFALFA observing day.

ALFALFA is drift scan, the 100p2 scan done on Dec. 1 2006 was at 24.333366 degrees declination so should be around AR 0.40x. The pity is they only had a 3 hour observation period that day and so far it appears the other observations were at high slew rates.
Joe

OK, if it wasn't ALFALFA, which of the other projects in the schedule for 01 Dec 06 would involve basketweave recording? I've looked at

A1852 To continue the monitoring of OH masers in high galactic latitude OH/IR stars (L-wide)
A2010 ALFALFA: The Arecibo Legacy Fast ALFA Survey (ALFA)
A2060 A GALFA Study of the Disk-Halo Interface (ALFA)
A2172 MAPPING HI IN A SPECTACULAR SHELL (ALFA)
A2200 HI Content of Distant Galaxy Clusters (ALFA)
A2220 Interfaces in the ISM: Mapping a Cold Cloud Boundary With GALFA (ALFA)

and ALFALFA still seems the best candidate. Maybe I'll have to correlate future outbreaks of VHAR WUs and see if I can identify the culprit......

(Edit - if anyone else wants to try and puzzle it out, you can reach that page, and others like it, from the 'Old Schedules' link here.)

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Message 693886 - Posted: 23 Dec 2007, 4:31:48 UTC - in response to Message 693787.

We may run out of work, but hopefully not for too long.

- Matt

Pity the next tape in the queue came from an Arecibo ALFALFA observing day.

ALFALFA is drift scan, the 100p2 scan done on Dec. 1 2006 was at 24.333366 degrees declination so should be around AR 0.40x. The pity is they only had a 3 hour observation period that day and so far it appears the other observations were at high slew rates.
Joe

OK, if it wasn't ALFALFA, which of the other projects in the schedule for 01 Dec 06 would involve basketweave recording? I've looked at

A1852 To continue the monitoring of OH masers in high galactic latitude OH/IR stars (L-wide)
A2010 ALFALFA: The Arecibo Legacy Fast ALFA Survey (ALFA)
A2060 A GALFA Study of the Disk-Halo Interface (ALFA)
A2172 MAPPING HI IN A SPECTACULAR SHELL (ALFA)
A2200 HI Content of Distant Galaxy Clusters (ALFA)
A2220 Interfaces in the ISM: Mapping a Cold Cloud Boundary With GALFA (ALFA)

and ALFALFA still seems the best candidate. Maybe I'll have to correlate future outbreaks of VHAR WUs and see if I can identify the culprit......

(Edit - if anyone else wants to try and puzzle it out, you can reach that page, and others like it, from the 'Old Schedules' link here.)

Let's see, the workunit header for 01dc06ag.18398.55642.16.6.147 says it was recorded Sat Dec 2 05:47:42 2006 and has a 1.3876 AR. The Arecibo schedules say AST on the left, and Atlantic Standard Time differs by 4 hours from UTC, so we need to look at the schedule for Dec. 2 at 01:47. That makes it A2060, I think.

WU 01dc06ag.16935.4162.10.6.171 was recorded Sat Dec 2 02:47:46 2006, which would convert to Dec. 1 at 22:47 AST, that's A2010 (ALFALFA) and the WU has an AR of 0.408 as expected. I also got some 01dc06af work from the ALFALFA observations with 0.408 AR.

I didn't get any from the middle of the 01dc06ag data, but considering how long the slewstorm has lasted I think the A1852 observations were probably high slew also.

My guess for the reason there's Dec. 2 data in a chunk labelled 01dc06 is that the hard disk recording was started on the first.
Joe

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Message 693927 - Posted: 23 Dec 2007, 14:21:47 UTC
Last modified: 23 Dec 2007, 14:23:15 UTC

I have to say I'm getting increasingly worried by this ongoing spate of apparent 'high slew' work.

Here's a new version of an old graph:


(direct link)

The 'historical' data I recorded from the start of MB up to the end of October 2007: it's been posted before, but I've rescaled the graph to show percentages rather than absolute numbers.

The 'current' data comes from six of the machines I'm monitoring for Joe's deadline re-estimation. I've only shown data from machines which have a 12-hour turnaround or less at these ARs: the plot is again a percentage, but the number of data points is comparable (3,110 historical: 2,126 current).

The significant new feature is the spike at AR=2.47, and a smaller spike between AR=7.5 and AR=8.5 Almost all of the work issued by SETI since about midday 22 December UTC has been at these extraordinarily high slew rates.

Joe and I have both looked at the recording schedules for Arecibo for 01Dec06 and 02Dec06, and I've also looked at 01/02Jan07. Neither of us has seen anything unusual in the pattern of observations which would account for these ARs.

Which leads me to wonder whether, just possibly, the ARs being inserted into the WU headers by the splitters could be corrupt?

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Message 693943 - Posted: 23 Dec 2007, 15:28:14 UTC - in response to Message 693927.
Last modified: 23 Dec 2007, 16:20:01 UTC

I have to say I'm getting increasingly worried by this ongoing spate of apparent 'high slew' work.


It does have a negative impact on the web server apparent performance...

Message boards : Technical News : Magic Dragon Theatre (Dec 21 2007)

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