RRD_PDPCALC(1) rrdtool RRD_PDPCALC(1) (NAME) rrd_pdpcalc - PDP Tianpeng Xia (DESCRIPTION) PDP . PDP (Refreshing some basics about PDP) (Fundamental knowledge) (man pages) . PDP . PDP : - Alex van den Bogaerdt. PDP << >> <> ( @oetiker ). << >> . - . <> PDP <> . Don Baarda UNKNOWN heartbeat . PDP . - Alex van den Bogaerdt. step . . . (Calculation logics) . Alex van den Bogaerdt @eotiker. (ASCII) . | | (v1) | _______ (v4) (v5) | | | (v3) ____________ | | | ______________| || | | | | | || || | | | | | || || | | | | (v2) | || || | | | |________| || || | ---------------------------------------------> 0 1 3 7 17 20 21 X ( ) Y . : - step - PDP PDP PDP - heartbeat - - v1 - Bogaerdt (Bogaerdt version) : ( GAUGE) step (normalization process) . (known) ( (unknown)) PDP . . : PDP (- - ...) . : - PDP (v1*3+v2*2)/5 - PDP (v2*2+v3*3)/5 - PDP (v3*5)/5 v3 - ... ( @oetiker): : - PDP (v1*3+v2*2)/5 - PDP (SAME) (v2*2+v3*8) - ... (A Comparison and some explanation) PDP . Bogaerdt PDP(6-10) PDP(11-15) . . Bogaerdt PDP . PDP(11-15) . . v3 . PDP PDP(6-10) (v2*2+v3*3)/5 PDP(11-15) (v3*5)/5 . PDP (steps) n PDP . PDP(6-10) PDP(11-15) . PDP(1-5) PDP(16-20) PDP(1-5) PDP(16-20) . PDP(6-10) PDP(11-15) (v2*2+v3*8) . (An example) . : rrdtool create target.rrd --start 1000000000 --step 5 DS:mem:GAUGE:20:0:100 RRA:AVERAGE:0.5:1:10 rrdtool update target.rrd 1000000003:8 1000000006:1 1000000017:6 \ 1000000020:7 1000000021:7 1000000022:4 \ 1000000023:3 1000000036:1 1000000037:2 \ 1000000038:3 1000000039:3 1000000042:5 rrdtool fetch target.rrd AVERAGE --start 1000000000 --end 1000000045 : create update fetch. rrd PDP rrd . (Focus on single steps) PDP . : 1000000005: 5.2000000000e+00 1000000010: 5.5000000000e+00 1000000015: 5.5000000000e+00 1000000020: 6.6000000000e+00 1000000025: 1.7333333333e+00 1000000030: 1.7333333333e+00 1000000035: 1.7333333333e+00 1000000040: 2.8000000000e+00 1000000045: nan 1000000050: nan : 1000000005 PDP 1000000001 1000000005 . 05 1000000005 . (data source) gauge . 05: 5.2 = (8*3+1*2)/5 10: 5.5 = (1*1+6*9)/10 15: 20: 6.6 = (6*2+7*3)/5 25: 1.73333 = (7+4+3+1*12)/15 ... 45: nan PDP(41-45) 50: nan PDP : (SUMMARY) <<>> PDP . (Other References) o PowerShell : o 1.11.0 2026-08-08 RRD_PDPCALC(1)