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Add debug output to understand calculation of failure probability (FP) #16

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Add debug output to understand calculation of failure probability (FP) #16

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17 changes: 16 additions & 1 deletion cmdline/device.c
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Original file line number Diff line number Diff line change
Expand Up @@ -438,13 +438,19 @@ static double SMART_198_R[SMART_MEASURES] = {
*/
static double smart_afr_value(double* tab, unsigned step, uint64_t value)
{
printf("|value=%ld|", value);
value /= step;
printf("|value/step=%ld|", value);

if (value >= SMART_MEASURES)
value = SMART_MEASURES - 1;

printf("|value=%ld|", value);

/* table rates are for a month, so we scale to a year */
return 365.0 / 30.0 * tab[value];
double result = 365.0 / 30.0 * tab[value];
printf("|result=%f|", result);
return result;
}

/**
Expand All @@ -464,14 +470,17 @@ static double smart_afr_value(double* tab, unsigned step, uint64_t value)
* we use the maximum rate reported, and we do not sum them,
* because the attributes are not independent.
*/
static double poisson_prob_n_or_more_failures(double rate, unsigned n);
static double smart_afr(uint64_t* smart, const char* model)
{
double afr = 0;
uint64_t mask32 = 0xffffffffU;
uint64_t mask16 = 0xffffU;

if (smart[5] != SMART_UNASSIGNED) {
printf("\n");
double r = smart_afr_value(SMART_5_R, SMART_5_STEP, smart[5] & mask32);
printf(" calculated AFR for SMART value 5: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}
Expand All @@ -480,6 +489,7 @@ static double smart_afr(uint64_t* smart, const char* model)
/* with some disks, only the lower 16 bits are significative */
/* See: http://web.archive.org/web/20130507072056/http://media.kingston.com/support/downloads/MKP_306_SMART_attribute.pdf */
double r = smart_afr_value(SMART_187_R, SMART_187_STEP, smart[187] & mask16);
printf("calculated AFR for SMART value 187: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}
Expand All @@ -497,24 +507,28 @@ static double smart_afr(uint64_t* smart, const char* model)
/* with Seagate disks, there are three different 16 bits value reported */
/* the lowest one is the most significant */
double r = smart_afr_value(SMART_188_R, SMART_188_STEP, smart[188] & mask16);
printf("calculated AFR for SMART value 188: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}

if (smart[193] != SMART_UNASSIGNED) {
double r = smart_afr_value(SMART_193_R, SMART_193_STEP, smart[193] & mask32);
printf("calculated AFR for SMART value 193: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}

if (smart[197] != SMART_UNASSIGNED) {
double r = smart_afr_value(SMART_197_R, SMART_197_STEP, smart[197] & mask32);
printf("calculated AFR for SMART value 197: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}

if (smart[198] != SMART_UNASSIGNED) {
double r = smart_afr_value(SMART_198_R, SMART_198_STEP, smart[198] & mask32);
printf("calculated AFR for SMART value 198: %f (%f%%)\n", r, poisson_prob_n_or_more_failures(r, 1) * 100);
if (afr < r)
afr = r;
}
Expand Down Expand Up @@ -725,6 +739,7 @@ static void state_smart(unsigned n, tommy_list* low)
if (devinfo->parent != 0 || !have_parent)
array_failure_rate += afr;

printf(" ");
printf("%4.0f%%", poisson_prob_n_or_more_failures(afr, 1) * 100);
}
}
Expand Down