uptime to nines

uptime-nines.ipynb

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   "source": [
    "import numpy as np"
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   "cell_type": "markdown",
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   "source": [
    "How do you get the number of nines from uptime percentage? Let's make some uptime percentages with clear 'nines' counts"
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     "text": [
      "99.99\n",
      "99.999\n",
      "99.9999\n",
      "99.99999\n",
      "99.999999\n",
      "99.9999999\n",
      "99.99999999\n",
      "99.999999999\n",
      "99.9999999999\n",
      "99.99999999999\n"
     ]
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   "source": [
    "pct = [90.0, 99.0, 99.9]\n",
    "for i in range(10):\n",
    "    pct.append( float(str(pct[-1]) + '9') )\n",
    "    print(pct[-1])"
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   "source": [
    "That last one is 13 nines.\n",
    "\n",
    "Convert uptime percentage to nines with a short formula:"
   ]
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   "id": "c36b2e15-ee26-4174-aa69-c1583d981d7e",
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   "source": [
    "nines = 2 - np.log10(100 - np.array(pct))"
   ]
  },
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    "and check it's correct:"
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     "data": {
      "text/plain": [
       "array([ 1.        ,  2.        ,  3.        ,  4.        ,  5.        ,\n",
       "        6.        ,  7.        ,  8.        ,  9.00000003, 10.00000027,\n",
       "       10.99999842, 11.99999225, 12.99980714])"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "nines"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e216756d-780b-4cee-863e-4519e6944dcb",
   "metadata": {},
   "source": [
    "95% is consider 1.5 nines, does it work?"
   ]
  },
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   "cell_type": "code",
   "execution_count": 14,
   "id": "d2779bef-9313-4fb4-9b3c-e1b0086b720d",
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "1.3010299956639813"
      ]
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     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "2 - np.log10(100 - 95)"
   ]
  }
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