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Add notes about EC brute-force

master
Vitaliy Filippov 2021-12-15 01:01:08 +03:00
parent 486d6774bd
commit f476eaa04b
1 changed files with 17 additions and 0 deletions
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17
afr.js
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@ -119,6 +119,23 @@ function cluster_afr_bruteforce({ n_hosts, n_drives, afr_drive, disk_heal_hours,
// AND for (1-AFR) portion of drive #2 death probability (all cases where #2 dies with #1 are already accounted)
// AND for (1-AFR)^2 portion of drive #3 death probability (#3 dying with #1 and #3 already accounted)
// AND so on
//
// EC 2+1:
// - Drive #1 dies within a year = A1
// - Drive #2 dies within +- recovery time around #1 death time = A1*2*L*A2
// - Drive #2 does not die within recovery time of #1
// - Drive #3 dies within +- recovery time around #1 death time = A1*(1-2*L*A2)*2*L*A2
// - Drive #3 does not die within recovery time of #1
// - Drive #1 does not die within a year = 1-A1
// - Drive #2 dies within a year = (1-A1)*A2
// - Drive #3 dies within +- recovery time around #2 death time = (1-A1)*A2*2*L*A3
// - Drive #3 does not die within recovery time of #2
// - Drive #2 does not die within a year
// - pg_death = A1*2*L*A2 + A1*(1-2*L*A2)*2*L*A2 + (1-A1)*A2*2*L*A3
// - A3 becomes A3*(1 - A1*2*L*A2 - (1-A1)*(1-A2))
// - A1 and A2 becomes 0
//
// So it just needs another part of brute-force :-)
let pg_set = [];
let per_osd = {};
/*