Root Access

3:31 AM

    OPS Mode. Output is in operations per second.
    File size set to 104857600 kB
    Record Size 4 kB
    Record Size 128 kB
    Record Size 4096 kB
    Command line used: /root/iozone3_430/src/current/iozone -O -s 100g -r 4k -r 128k -r 4m -b /root/results.xls
    Time Resolution = 0.000001 seconds.
    Processor cache size set to 1024 kBytes.
    Processor cache line size set to 32 bytes.
    File stride size set to 17 * record size.
                                                          random    random     bkwd    record    stride

@allquixotic ^

first set of 3 is with compression off, second is with compression lz4

oldmud0

4:05 AM

Hmm, I'm wondering how bans are going to work if I use websockets as a proxy between the web browser and some UDP game servers..

HackToHell

4:51 AM

Very tempted to move from 8.1 to Win 10 Technical preview

HackToHell

6:27 AM

@JourneymanGeek What was the name of the botnet that compromised your BuyVM node?

Journeyman Geek

7:19 AM

@HackToHell: errrr

XOR/DDOS

blog.avast.com/2015/01/06/…

@HackToHell: Oddly enough, I think I have a copy of the entire filesystem of that system somewhere

4

Q: Purpose of breadboard "studs" on base off micro breadboards?

I recently bought some micro breadboards on Ebay. Extremely useful little things. However each have two awkward studs on their bases. See the attached photo. What I'm curious about is their purpose? What might these "plugin" to or be used for? I think I'm going to file them off.

breadboard

whoa

allquixotic

10:22 AM

@Bob are you saying I should turn it on? :P and what kind of data is it reading/writing, anyway? random data? if it's random, lz4 should not compress it well at all (high entropy)

Bob

10:42 AM

@allquixotic default is compressible

not sure what ratio though

see the -+w option

and the dedup var => iozone.org/src/current/iozone.c

can't seem to find the default though

HackToHell

@JourneymanGeek Aha

Gonna include that in my post on security policies (and why we should enable SSH keys) in my company wiki

Bob

In fact... dunno if I'm reading this correctly, but is dedup set at all when -+w isn't passed?

allquixotic

@Bob the problem is, unless they're putting in some kind of good "representative" data (of what? English text? WAV files? MP3s? H265 data? gigabytes of zeroes?) it's hard to know what kind of result we should expect

and you can pretty much tailor the results to what you want them to be - which is only meaningful if your actual data is like that.

most of my data, by bulk, is going to be already highly compressed

LZ4 will only slow it down

Bob

11:01 AM

@allquixotic I'm not looking for real-world results here. Partially because I don't know what my data will be, and partially because my data will be so varied that it would be at least somewhat compressible.

I'm primarily interested in the no-compression and incompressible cases (=> currently rerunning incompressible on lz4)

@allquixotic No. It would only 'slow it down' if your CPU is completely saturated.

You're still constrained by disk speed, and lz4 won't increase the size of incompressible data (at least, not to any extent you'd notice... hopefully)

Overall? Still worth enabling, if only to compress, say, the Windows OS in your VM.

> Performance on modern CPUs often exceeds 500 MB/s on compression and over 1.5 GB/s on decompression and incompressible data (per single CPU core).

Since the ARC is always uncompressed, the only time you'd ever experience a potential slowdown is while hitting your HW RAID cache.

But since it's only 1 GB, even that would be minor.

allquixotic

Still, it's unnecessary CPU cycles being used - ones that could be used for the likely scenario of having some kind of simulation game running on the server.

Bob

> These numbers were obtained using a development build on an HP MicroServer with a 1.3 GHz dual-core 64-bit Athlon II processor with 8GB of RAM.

allquixotic

Many simulation games don't deal with a huge amount of I/O (they reference a third-party database, which does its own compression) but they use a lot of CPU cycles, and if they reach saturation because the FS is using more cycles than it should, you can get saturation where you might not get it otherwise

or worse saturation if it's unavoidable

the things I need compressed can be compressed at the application layer.

Bob

11:17 AM

Somehow, I get the feeling that time spent on compression in a 2014 Xeon CPU would be absolutely negligible.

allquixotic

also consider that I might want to use some other compression algorithm, depending on the specific workload of the program, that might do better than LZ4

Bob

Considering they apparently went over 500 MB/s on that puny CPU.

allquixotic

for infrequent compression I could use LZMA2 (if I don't frequently update the data)

or I could use Speedy if performance is even more critical than LZ4

Bob

The point of compression is to improve overall performance by reducing disk accesses.

allquixotic

or if lossy is okay (media), I can use a lossy algorithm

Bob

11:18 AM

But you can set (or disable) compression on a per-dataset basis anyway.

lz4 just makes a good catchall algorithm

allquixotic

@Bob It's physically impossible for a compression algorithm to not add some size to data it has compressed, even if it is able to do better than Zip (which is notoriously awful at making compressed data huge) - if all the data that counts is already compressed, how many disk accesses is it actually saving?

sure, it might make startup marginally faster since the binaries of core system files aren't compressed (ELF doesn't support it AFAIK, unless you upx everything), but they sit more or less permanently either mapped into RAM by processes or ARC mere seconds after system bootup

Bob

(Generously) assuming your HDDs manage 200MB/s, that might produce a load of 0.03 on your CPU (out-of-my-arse number from the AthlonII throughput and CPU benchmarks).

@allquixotic It could be as simple as flagging a specific file (or block) as incompressible in the FS metadata.

allquixotic

other than that, I'll have huge collections of MP3s and/or video that do not benefit at all from being LZ4'ed, and probably a pgsql database that's been compressed

Bob

Not saying that they do that, but they probably already considered that case.

Whoops, 0.36.

allquixotic

I'll give it a try, but I doubt it provides any real benefit in my use cases, and might actively hurt some things depending on how smart their incompressible detection is

0.36 is a lot

Bob

11:25 AM

Yea, miscalc'd.

allquixotic

BBL

Bob

@allquixotic You can always do a real-world benchmark (use dd to simulate copying a compressed file? and look at the CPU load)

Though, I'm not sure if dd on a single thread is sufficient :P

Make sure you compare with compression off

I'd do the test myself, but I'm already running a bench. I'll try it later if you haven't.

Journeyman Geek

@HackToHell glad to be a negative example ;p

@HackToHell: Another advantage is you can give access to an account (say root) to more than one person, and delete the key if they leave. (and someone will let me and know you know if this is a horribad idea ;p)

yay, got the good ending of dishonoured.

Bob

Yep, horribad describes it nicely.

Journeyman Geek

Now... I can kill everyone.

._.

Bob

11:31 AM

Give someone root and they could install any manner of backdoors.

HackToHell

I wrote no one's supposed to login as root

Journeyman Geek

THAT WORD. IT MIGHT MEAN WHAT YOU THINK IT MEANS.

HackToHell

And no sudo to anyone :P

Journeyman Geek

@HackToHell: admins may need it

HackToHell

Except them of course :P

Journeyman Geek

11:32 AM

sudo might be a better idea than root.

And keys anyway ;p

Bob

Apparently I'm role-playing Gordon Freeman now.

(Just spent an afternoon knocking down drywall with a crowbar.)

HackToHell

I'm pretty darn sure this is outdated

660

Q: XKCD #936: Short complex password, or long dictionary passphrase?

How accurate is this XKCD comic from August 10, 2011? I've always been an advocate of long rather than complex passwords, but most security people (at least the ones that I've talked to) are against me on that one. However, XKCD's analysis seems spot on to me. Am I missing something or is th...

cryptography passwords entropy

I need a good strong password link hmm

Journeyman Geek

Heh

For single use passwords, I tend to generate them here fourmilab.ch/hotbits

HackToHell

Site uses Java :O :O

Journeyman Geek

naw, it works without it

wierdly, java is for sound

HackToHell

12:10 PM

Journeyman Geek

o0

Bob

1:22 PM

Oh wow.

I was just asked if one should replace an ATI Radeon HD 4350 with an Nvidia GeForce GT 210.

Yes. ATI.

Yes. 210.

Yes, worse than Ivy Bridge iGPU (and probably Sandy too)

HackToHell

Blah Azure's VNet implementation is driving me mad

Journeyman Geek

lol

What's the actual system?

Bob

@JourneymanGeek The one with the ancient GPUs?

Journeyman Geek

Yup

Bob

@JourneymanGeek I believe it's a c2d. Some Dell Studio line machine.

Journeyman Geek

1:36 PM

That might make sense in some cases

Granted I went with a 450

Bob

@JourneymanGeek I told them to stick with the ATI.

Benchmark scores are close enough and the most graphics-intensive activity is probably watching videos.

Journeyman Geek

@Bob: If it fails tho...

Bob

@JourneymanGeek ?

Journeyman Geek

oh, I mean, if it has no integrated GPU and the existing video card failed, it might be a decent replacement

Bob

@JourneymanGeek Sure, but it's not worth replacing at the moment.

HackToHell

1:45 PM

Okay I don't understand IpSec, openswan or any of this shit

Site to Site vpn through openvpn it is then

Journeyman Geek

yeah

HackToHell

Right now i need to figure out how to do that, it's been years since I touched openvpn

allquixotic

5:45 PM

@Bob it's incredible what old crap beater machines people have laying around, and then they act insulted when you say their hardware is horrible and they need to upgrade

"What? It's only 8 years old!" - as if their PC should last as long as an aircraft carrier

DragonLord

7:07 PM

USWNT made it to the finals again.

I don't normally follow association football, but there's a good shot US will make it this time around in the Women's World Cup.

Four years ago, the US lost to Japan on penalty kicks.

Braiam

8:55 PM

nuuu @jou approving a suggested edit on spam :( superuser.com/review/suggested-edits/175319

no bones for a week!

mdszy

10:04 PM

Oh man this brings back memories.

DragonLord

11:10 PM

Reddit is falling apart.

It's likely mods and admins were bribed with at least several hundred thousand dollars to remove certain content causing censorship to occur (most notably TPP-related matters)

How can we outmuscle Big Media...

This bribery is probably under NDA so we might never see an official explanation. The mods and admins are forced to stay silent about it lest they lose the money and risk getting sued.

allquixotic

11:34 PM

@DragonLord I was under the impression that mods were poise against the admins and the Reddit corporation

are you saying they are in league with them?

DragonLord

@allquixotic Not all, but /r/news and /r/worldnews seem to have tainted mods; most others seem to be okay

mdszy

11:59 PM

I've just stopped using reddit.

I don't even care anymore.

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