How do calculate discounted frontend classes instance hours?

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pdknsk

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Dec 14, 2011, 12:02:54 AM12/14/11
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The docs are not very helpful on this.

http://code.google.com/appengine/docs/billing.html#Billable_Resource_Unit_Cost

Frontend Instances (F1) Instance hours $0.08
Frontend Instances (F2) Instance hours $0.16
Frontend Instances (F4) Instance hours $0.32
Discounted Instances Instance hours $0.05

So does the same rate apply, like this?

F1 - $0.05
F2 - $0.10
F4 - $0.20

And when I want to pre-purchase 25 F4 hours at the discounted rate, do
I just set 100 discounted instance hours then?

Or is the discount only available for F1?

Gregory D'alesandre

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Dec 14, 2011, 1:01:41 AM12/14/11
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Your assessment is completely correct (except for the last question), we'll work on doing a better job in documenting the way discounted instance hours are used for Frontend classes.

Greg


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gregsz

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Dec 19, 2011, 11:17:42 PM12/19/11
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I'm considering using GAE to build a SaaS business but am having a real hard time finding a way to forecast my hosting costs.  Even if I were a coder and understood the details about how I'll be billed, how could I make a decent estimation of what additional costs I'll incur per new customer using my online B2B service on a daily or monthly basis?  I've been searching the GAE site and the community but haven't found anything yet.  Anybody have a good suggestion about how to do this?  Is there a rule of thumb?  I'm obviously hesitant to use the platform to build my app if I can't make some reasonable estimation of my costs.  much appreciated!

Emanuele Ziglioli

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Feb 13, 2012, 3:54:03 PM2/13/12
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Can you explain what I see on the Billing History?

Resource Used Free Billable Charge
Frontend Instance Hours
$0.08/Hour 96.36 96.36 96.36 $5.47

I'm running 1 F4 instance 24/7 with occasional spikes.
So I understand that 1 F4 instance generates 4x24 = 96 instance hours
per day.
One instance hour costs $0.08 so the cost of 96 instance hours should
be 96 x $0.08 = $7.68

Why am I being charged $5.47? what's that 96.36 under Free?

If I want to purchase discounted instance hours in advance for 1 F4
instance to run 24/7, should I purchase: 4x24x7 = 672 instances?

Thanks,
Emanuele (app id: sirtrackwms)

Gregory D'alesandre

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Feb 13, 2012, 4:08:39 PM2/13/12
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Hi Emanuele,

That display looks like a bug (that I'll look into), you should see 28 Free Hours / day.  So your bill should be (96.36-28) * $0.08 = $5.47.  So the monetary calculation is happening correctly but the display is not correct.  If you wanted to use discounted instance hours and you use precisely 96/day then you should choose 476 (which is (96-28)*7) per week.

I hope that helps!

Greg

Emanuele Ziglioli

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Feb 13, 2012, 4:18:01 PM2/13/12
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Thanks Greg, now it makes sense!

Gregory D'alesandre

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Feb 13, 2012, 8:09:19 PM2/13/12
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Also, there was indeed a bug introduced last release with the billing reports, that bug has now been fixed and you should see a new and more accurate billing report for your app.

Greg

Emanuele Ziglioli

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Feb 13, 2012, 8:39:58 PM2/13/12
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Awesome!

Also, I find it a bit confusing when I read about instance per hour
and related costs. I never know whether it's per day or per week. For
example, when we book some discounted instance hours in advance, we
need to enter the amount per week. But when the bill shows up, that's
per day. Similarly, the billing period seems to be weekly, despite
being able to see a bill every day.
The pricing here is specified (as stated) per day:
http://www.google.com/enterprise/cloud/appengine/pricing.html
It would be helpful if you could be more clear and consistent with
that simple aspect.

Cheers,
Emanuele

Gregory D'alesandre

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Feb 13, 2012, 8:48:54 PM2/13/12
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Thanks for the feedback Emanuele.  I can certainly see where you are coming from.

Greg

Brandon Wirtz

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Feb 13, 2012, 8:49:54 PM2/13/12
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It's about buckets :-)

Your refill bucket on discount hours is weekly, but you can use them all the
first day if you like.

This is better for me, we have big days when certain TV shows Air and we
consume 90% of our hours one day. So a weekly discount works well for us.

Emanuele Ziglioli

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Feb 15, 2012, 3:08:22 PM2/15/12
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Well, I thought my new billing period would start from the 13th but
the bill on that day still doesn't show or seem to use discounted
instance hours:

Usage Report for 2012-02-13
Frontend Instance Hours
$0.08/Hour 96.59 28.00 68.59 $5.49
Discounted Instance Hour
$0.05/Hour 0.00 0.00 0.00 $0.00

Could anybody ahave a look?
(id: sirtrackwms)

Thank you

Gregory D'alesandre

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Feb 15, 2012, 3:21:16 PM2/15/12
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Since you had a charge yesterday I expect the discounted instance hours to take effect today.  They take effect after the next billing cycle after you change the number.

Greg

Emanuele Ziglioli

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Feb 15, 2012, 5:40:49 PM2/15/12
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Hi Greg,

the latest bill has just appeared and it shows discounted instance
hours correctly.

Thank you


Usage Report for 2012-02-14

Frontend Instance Hours
$0.08/Hour 28.00 28.00 0.00 $0.00
Discounted Instance Hour
$0.05/Hour 68.80 0.00 68.80 $3.4
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