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Date: Fri, 10 Mar 2023 00:02:23 +0100
From: Solar Designer <>
Subject: Re: John the Ripper in the cloud update 2023/02

On Thu, Mar 09, 2023 at 12:21:12AM -0300, Rodrigo s wrote:
> Really thanks for your help! I am really happy to say that it works now.
> All I did was exactly what that link said
> <>  to
> do. I put a random number like 80. After a day the AWS accepted.
> Summary of service quota(s) requested for increase:
> [US East (Northern Virginia)]: EC2 Instances / nu.general (All
> Standard (A, C, D, H, I, M, R, T, Z) instances), New Limit = 80

That's great, but now you can no longer help us test if our new default
instance type would have worked with AWS defaults.

> Now... I can't say if it was what you did to solve the problem. But, after
> I try again, using the same default configuration, it works without any
> problem and I have the Linux console. I can learn more and understand how
> all of it works.

I think what really made the "same" default configuration work is that
I've changed the default instance type from p3.2xlarge to c6i.large.

p3.2xlarge wouldn't work for you even after the quota increase, because
P isn't among the instance type letters that you increased the quota
for.  c6i.large was expected to work even before your quota increase,
because it needs 2 vCPUs and the default is apparently 5, which you've
now increased to 80.

> But I am a little disappointed. I thought it could be extremely faster than
> what I can do myself on my computer.

c6i.large is certainly not extremely fast.  Their largest in that
category is c6i.32xlarge, which is 64 times larger - it has 128 vCPUs,
so wouldn't even fit in your increased quota now.  You can now try e.g.
c6i.16xlarge, which has 64 vCPUs.

> In my test (trying a random format I
> was using), it was doing  about 12.555KC/s in each thread, so 12,5k *2 =
> 25KC/S. In my computer the same operation make 4,3KC/s in 12 threads or
> about 50KC/S

If you have 12 vCPUs (hardware threads), no surprise they're faster than
the 2 in AWS.  However, apparently those in AWS are faster than yours
each, perhaps because c6i instances have AVX-512 and your CPU does not.

You'll need to mention what this "random format" was, or better yet show
the "Loaded ..." lines, for me (and maybe others in here) to comment
whether those speeds are good or bad, and maybe how to improve them.

> Because we can easily "build" a new computer in AWS, I thought this bundle
> could have the best possible configuration. What really makes the program
> work faster? I always have this question in my mind. So, with AWS I could
> test it.

Yes, you can test different kinds of hardware quickly, like Intel vs.
AMD (c6i vs. c6a instances for the latest ones).

> What do you think about it? Is there a cheap configuration in AWS? Or to it
> work, I just need to pay for the most expensive options in AWS?

For continued use over months or years, AWS is more expensive than
buying your own hardware (but then you also need to maintain the
hardware, and cost of that depends on cost of your time).  It is also
more expensive than renting dedicated servers (but then you're tied to
specific hardware and need to manage the OS and software installs).

For occasional uses and experiments (up to days or weeks, but not
months), or e.g. when you don't know how long an attack will take (with
luck, can be quick), AWS can be cheaper.

> There is no shortcut for it?

As explained on John the Ripper in the cloud homepage, usage of spot
instances is a partial shortcut to reduce AWS costs.

Please note that there's a separate service quota for spot instances.
Your increase from 5(?) to 80 probably only applies to on-demand
instances of those categories.  You're probably still limited to 5 spot
instance vCPUs (if not to 0?), and you'll probably want to request an

Meanwhile, you can try running up to c6i.16xlarge as on-demand and up to
c6i.xlarge as spot.

> I really would like to help with this AWS project. Because I am still a
> noob, I can just think about how to do it. But I can study if you say that
> what I show makes sense :)

So far you're experimenting and learning.  This makes sense.


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