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Old 2021-06-06, 15:03   #1673
chalsall
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"Chris Halsall"
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Quote:
Originally Posted by kriesel View Post
Care to post a how-to for that GCE?
Would love to. But time is a non-renewable resource...

To add to MooMoo2's excellent notes, I would say that for my own use-case (P-1'ing) I concluded that GCE's "c2-standard-8" instances were optimal (8-v-core (read: 4 usable cores) and 32 GB of RAM).

Be sure to select the "Preemptible" option. This is a /bit/ like Amazon's "Spot", but different. Basically, you get the kit for no more than 24 hours. But at something like 25% of the cost. The storage is persistent, so you just restart the instance when it stops; this can be done programmatically.

Lastly, for those leveraging on the "Free Trial ($300 USD)" you'll find that you are constrained in only having eight (8#) v-cores active at any one time in the same region.

Thus... You'll actually have to spin up something like three or four different (cloned) instances in different regions just to be able to use up the $300 credit in the 90 days the credits are valid for.

Hope that helps. Happy to answer any questions anyone has.

(Moderators: Perhaps this and above should be split out into another thread, or joined to an existing one.)
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Old 2021-06-17, 21:07   #1674
chalsall
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Default Empirically the Gods have a wicked sense of humor...

Last night a major storm passed over Barbados. It had so much sheet lightning that it was a bit like the entire country was in a rave with strobe lights.

A ground strike near me was observed at approximately 0200. And then about 200 milliseconds later heard. The power failed instantly...

Power was restored at ~1230 hours. Burrow (my main workstation) was declared dead at ~1300 hours (after removing every component and swapping out the PSU).

New MB (GigaByte B365M DS3H) and CPU (i5-9400) procured COTS at ~1400.

I'm typing this within the new environment. The good news is the RAM, GPU, HDDs, and SSD survived, so I'm back to my nominal three-screen set-up.

The bad news is some of our friends won't have power for a day or so, and they (or, at least, their vehicles) are "locked-in" because their electrical gates won't operate, and they don't have manual overrides...

True story. It can be interesting living in "paradise".
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Old 2021-06-17, 21:25   #1675
Viliam Furik
 
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Quote:
Originally Posted by chalsall View Post
A ground strike near me was observed at approximately 0200. And then about 200 milliseconds later heard. The power failed instantly...

Power was restored at ~1230 hours. Burrow (my main workstation) was declared dead at ~1300 hours (after removing every component and swapping out the PSU).
I understand the power fail. Computer being affected I don't. Was it due to you not having the appropriate safety measures for the power (extension cord with fuse, overcurrent, overload, and other over- protections in PSU), or you did have those, but they didn't help? I really don't know if a lightning strike can cause damage even with all those safety measures.

Once, not so long ago, maybe one or two years back, a lightning stroke our building (most probably, but I don't have it confirmed). It's a 7-story prefab building, with a proper lighting rod installed on the roof, and going down to the ground in multiple places. Even our water pipes are connected to the lightning rods, which was a surprise to me but is probably common.

When it hit, I heard a considerably loud thunder, which led me to the immediate conclusion that our building was hit. I think I even felt a little tremor. The lights went out for a second or two, the monitor went out for about the same time, but then everything was working as if nothing happened.

Take my only experience with lightning strikes with a grain of salt, enough time has passed for my memory to be corrupted.
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Old 2021-06-17, 21:34   #1676
Uncwilly
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Quote:
Originally Posted by chalsall View Post
A ground strike near me was observed at approximately 0200. And then about 200 milliseconds later heard. The power failed instantly...
~70m away? I have been within 100m of a strike before. Some friends were within 30m of that strike (having just walked by the tree that was hit.) It was intensely bright and the sound arrived about the time that the brain figured out that it was lightning. There were screams in the room that I was in and someone fell out of their seat (neither were me).
Quote:
Power was restored at ~1230 hours. Burrow (my main workstation) was declared dead at ~1300 hours (after removing every component and swapping out the PSU).

New MB (GigaByte B365M DS3H) and CPU (i5-9400) procured COTS at ~1400.
I would have thought that you would have a robust panel at the mains with breakers etc. designed to handle this. You do get a reasonable amount of jolts, no? Also, shouldn't that machine have at the wall a high performance SS and then a UPS?

Last fiddled with by Uncwilly on 2021-06-17 at 21:41
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Old 2021-06-17, 21:45   #1677
chalsall
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Quote:
Originally Posted by Viliam Furik View Post
I understand the power fail. Computer being affected I don't.
Nor do I. And I don't like not understanding. I'm modeling in my head right now (and reviewing every connective path) what could possibly have occurred.

Multiple UPSs were in place for the power. And we're on fiber for our IP. I have experienced before where the neutral gets hit by lightning, and the ground-ties aren't capable of sinking the sudden incredible voltage differential.

And, of course, the death of Burrow might simply have been correlative rather than causal. The other machines I have running here all survived.

Last fiddled with by chalsall on 2021-06-17 at 21:49 Reason: s/incredible load/incredible voltage differential/; # Nomenclature is important; I probably don't even have this correct.
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Old 2021-06-17, 21:56   #1678
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Maybe it was an EMP test by Trinidad.
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Old 2021-06-17, 22:07   #1679
chalsall
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Quote:
Originally Posted by Uncwilly View Post
Maybe it was an EMP test by Trinidad.
Thanks for that. Sincerely. First laugh I've had today!
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Old 2021-06-18, 04:16   #1680
kriesel
 
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Quote:
Originally Posted by chalsall View Post
Nor do I. And I don't like not understanding. I'm modeling in my head right now (and reviewing every connective path) what could possibly have occurred.
It could have been worse. Tree struck the day before still burning.

Long ago I saw at close range outdoors a bolt pass through a maple tree's canopy and jump to the above-ground phone line. I found out later it blew the wall mounted junction box apart in the kitchen, followed the phone cord to jump to some aluminum trim, blasted a chunk out of the countertop on its way to the sink and plumbing, and missed possibly zapping the stepmother's head by 5 minutes; she'd been on the phone earlier. That was back before cell or wireless phones, might have been a party line yet then. Years earlier a tall 82 year old pine on the other side of the house took a hit on its north side, blasting bark off as the sap was vaporized explosively by the large current, doing enough damage it had to be removed a few years later.

Where I used to work, lightning hits in the area would sometimes induce enough ground potential to blow out 2500V optoisolators from one building to the next. They were replaced with full fiber optic runs.

Something that can jump cloud to ground, isn't going to be stopped by a few inches or feet of airgap around protective elements. https://www.weather.gov/safety/lightning-power 300MV, 30kA packs a punch.

Last fiddled with by kriesel on 2021-06-18 at 04:27
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Old 2021-06-18, 04:46   #1681
retina
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Quote:
Originally Posted by kriesel View Post
Something that can jump cloud to ground, isn't going to be stopped by a few inches or feet of airgap around protective elements. https://www.weather.gov/safety/lightning-power 300MV, 30kA packs a punch.
It's all about the joules, not the voltage or the current. More joules = more kills.

In theory you could have a capacitor charged to 300MV and deliver 30kA into a short. But if it only lasts a few femtoseconds then it won't matter, there aren't enough joules to do much damage.
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Old 2021-06-18, 04:55   #1682
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The link also states a discharge contains energy equivalent to ~100W x 3 months, which is ~800MJ.

Last fiddled with by kriesel on 2021-06-18 at 04:58
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Old 2021-07-02, 16:29   #1683
xilman
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I have some good news and some bad news. Let's start with the bad news.

It appears that I may have gout in or around my left ankle and have been largely out of action for 4 days. It's possible that colchicine might fix it and I hope to find out in the next 24 hours.

Colchicine is evil stuff. The lethal dose isn't very much larger than the therapeutic dose, which is why the medics are loathe to prescribe it and then only in small quantities.

Good news in the Happy Me thread.
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