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Problem report
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Resolution: Won't fix
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Trivial
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None
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4.0.22
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None
When calculating 'used' file system size agent subtracts free blocks from total blocks. But when calculating 'pused' agent uses available blocks rather than free blocks and used+available as total size rather than total blocks.
if (NULL != total) *total = (zbx_uint64_t)s.f_blocks * s.ZBX_BSIZE; if (NULL != free) *free = (zbx_uint64_t)s.f_bavail * s.ZBX_BSIZE; if (NULL != used) *used = (zbx_uint64_t)(s.f_blocks - s.f_bfree) * s.ZBX_BSIZE; if (NULL != pfree) { if (0 != s.f_blocks - s.f_bfree + s.f_bavail) *pfree = (double)(100.0 * s.f_bavail) / (s.f_blocks - s.f_bfree + s.f_bavail); else *pfree = 0; } if (NULL != pused) { if (0 != s.f_blocks - s.f_bfree + s.f_bavail) *pused = 100.0 - (double)(100.0 * s.f_bavail) / (s.f_blocks - s.f_bfree + s.f_bavail); else *pused = 0; }
As the result used + free is not equal to total (there can be ~5% difference), also pused, pfree also differs by few percents from value calculated by using total, used, free statistics.
The explanation of used statvfs free/available metrics:
fsblkcnt_t f_blocks; /* size of fs in f_frsize units */
fsblkcnt_t f_bfree; /* # free blocks */
fsblkcnt_t f_bavail; /* # free blocks for unprivileged users */