WesandClaude Sonnet 4.5
27afedb32e
Fetches SMART data from Scrutiny's InfluxDB and calculates failure probabilities using the exact BackBlaze tables from SnapRAID source. Key features: - Calculates both v12 (with attr 193) and v13 (without attr 193) algorithms - v12 matches SnapRAID pre-v13.0 (includes Load Cycle Count) - v13 matches modern SnapRAID v13.0+ (excludes Load Cycle Count) - Stores both values for trending and comparison - Correctly applies bit masks (16-bit for 187/188, 32-bit for others) - Annualizes monthly rates and applies Poisson distribution - Logs to PostgreSQL with device metadata Solved the mystery: SnapRAID v12 uses attribute 193 which was removed in v13.0. Load cycle count has massive impact on failure predictions for some drives (80% vs 4% difference). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
45 lines
1.5 KiB
Python
45 lines
1.5 KiB
Python
#!/usr/bin/env python3
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"""Test BackBlaze calculation with different values"""
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import math
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from backblaze_tables import SMART_5_R, SMART_187_R, SMART_188_R, SMART_197_R, SMART_198_R
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def poisson_prob(rate):
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"""Calculate P(at least 1 failure) = 1 - e^(-rate)"""
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return 1 - math.exp(-rate)
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def test_calculation(attr_value):
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"""Test with a given attribute value"""
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# Scale monthly to annual (like snapraid does)
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afr_5 = (365.0 / 30.0) * SMART_5_R[min(attr_value, 255)]
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afr_187 = (365.0 / 30.0) * SMART_187_R[min(attr_value, 255)]
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afr_188 = (365.0 / 30.0) * SMART_188_R[min(attr_value, 255)]
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afr_197 = (365.0 / 30.0) * SMART_197_R[min(attr_value, 255)]
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afr_198 = (365.0 / 30.0) * SMART_198_R[min(attr_value, 255)]
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# Take maximum (like snapraid)
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max_afr = max(afr_5, afr_187, afr_188, afr_197, afr_198)
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# Apply Poisson
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prob = poisson_prob(max_afr) * 100
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return max_afr, prob
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print("Testing different attribute values:")
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print("=" * 80)
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for test_val in [0, 50, 100, 150, 200, 255]:
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afr, prob = test_calculation(test_val)
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print(f"Attribute value {test_val:3d}: AFR={afr:.4f}, Probability={prob:.2f}%")
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print("\n" + "=" * 80)
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print("What we're seeing from /dev/sdc:")
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print(" All critical attributes: RAW_VALUE=0, VALUE=100")
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print(" SnapRAID reports: 81%")
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print(" Our calculation with value=0: ", end="")
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afr0, prob0 = test_calculation(0)
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print(f"{prob0:.2f}%")
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print(" Our calculation with value=100:", end="")
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afr100, prob100 = test_calculation(100)
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print(f"{prob100:.2f}%")
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