Browse Source

Merge all 4 calculation functions into one, fix very small number formatting

Also fix host failure calcuation - still not ideal, but closer to reality
master
Vitaliy Filippov 6 months ago
parent
commit
233c734775
  1. 90
      afr.js
  2. 27
      main.js

90
afr.js

@ -8,7 +8,6 @@ module.exports = {
cluster_afr_fullmesh,
failure_rate_fullmesh,
cluster_afr,
print_cluster_afr,
c_n_k,
};
@ -56,85 +55,24 @@ function failure_rate_fullmesh(n, a, f)
// is that, with k=2, total failure rate doesn't depend on number of peers per OSD,
// because it gets increased linearly by increased number of peers to fail
// and decreased linearly by reduced rebalance time.
function cluster_afr_pgs({ n_hosts, n_drives, afr_drive, capacity, speed, replicas, pgs = 1, osd_rm, degraded_replacement, down_out_interval = 600 })
function cluster_afr({ n_hosts, n_drives, afr_drive, afr_host, capacity, speed, ec, ec_data, ec_parity, replicas, pgs = 1, osd_rm, degraded_replacement, down_out_interval = 600 })
{
pgs = Math.min(pgs, (n_hosts-1)*n_drives/(replicas-1));
const pg_size = (ec ? ec_data+ec_parity : replicas);
pgs = Math.min(pgs, (n_hosts-1)*n_drives/(pg_size-1));
const host_pgs = Math.min(pgs*n_drives, (n_hosts-1)*n_drives/(pg_size-1));
const resilver_disk = n_drives == 1 || osd_rm ? pgs : (n_drives-1);
const disk_heal_time = (down_out_interval + capacity/(degraded_replacement ? 1 : resilver_disk)/speed)/86400/365;
return 1 - (1 - afr_drive * (1-(1-(afr_drive*disk_heal_time)**(replicas-1))**pgs)) ** (n_hosts*n_drives);
}
function cluster_afr_pgs_ec({ n_hosts, n_drives, afr_drive, capacity, speed, ec: [ ec_data, ec_parity ], pgs = 1, osd_rm, degraded_replacement, down_out_interval = 600 })
{
const ec_total = ec_data+ec_parity;
pgs = Math.min(pgs, (n_hosts-1)*n_drives/(ec_total-1));
const resilver_disk = n_drives == 1 || osd_rm ? pgs : (n_drives-1);
const disk_heal_time = (down_out_interval + capacity/(degraded_replacement ? 1 : resilver_disk)/speed)/86400/365;
return 1 - (1 - afr_drive * (1-(1-failure_rate_fullmesh(ec_total-1, afr_drive*disk_heal_time, ec_parity))**pgs)) ** (n_hosts*n_drives);
}
// Same as above, but also take server failures into account
function cluster_afr_pgs_hosts({ n_hosts, n_drives, afr_drive, afr_host, capacity, speed, replicas, pgs = 1, osd_rm, degraded_replacement, down_out_interval = 600 })
{
const otherhosts = Math.min(pgs, (n_hosts-1)/(replicas-1));
pgs = Math.min(pgs, (n_hosts-1)*n_drives/(replicas-1));
const resilver_disk = n_drives == 1 || osd_rm ? pgs : (n_drives-1);
const pgh = Math.min(pgs*n_drives, (n_hosts-1)*n_drives/(replicas-1));
const disk_heal_time = (down_out_interval + capacity/(degraded_replacement ? 1 : resilver_disk)/speed)/86400/365;
const host_heal_time = (down_out_interval + n_drives*capacity/pgs/speed)/86400/365;
const p1 = ((afr_drive+afr_host*pgs/otherhosts)*host_heal_time);
const p2 = ((afr_drive+afr_host*pgs/otherhosts)*disk_heal_time);
return 1 - ((1 - afr_host * (1-(1-p1**(replicas-1))**pgh)) ** n_hosts) *
((1 - afr_drive * (1-(1-p2**(replicas-1))**pgs)) ** (n_hosts*n_drives));
}
function cluster_afr_pgs_ec_hosts({ n_hosts, n_drives, afr_drive, afr_host, capacity, speed, ec: [ ec_data, ec_parity ], pgs = 1, osd_rm, degraded_replacement, down_out_interval = 600 })
{
const ec_total = ec_data+ec_parity;
const otherhosts = Math.min(pgs, (n_hosts-1)/(ec_total-1));
pgs = Math.min(pgs, (n_hosts-1)*n_drives/(ec_total-1));
const resilver_disk = n_drives == 1 || osd_rm ? pgs : (n_drives-1);
const pgh = Math.min(pgs*n_drives, (n_hosts-1)*n_drives/(ec_total-1));
const disk_heal_time = (down_out_interval + capacity/(degraded_replacement ? 1 : resilver_disk)/speed)/86400/365;
const host_heal_time = (down_out_interval + n_drives*capacity/pgs/speed)/86400/365;
const p1 = ((afr_drive+afr_host*pgs/otherhosts)*host_heal_time);
const p2 = ((afr_drive+afr_host*pgs/otherhosts)*disk_heal_time);
return 1 - ((1 - afr_host * (1-(1-failure_rate_fullmesh(ec_total-1, p1, ec_parity))**pgh)) ** n_hosts) *
((1 - afr_drive * (1-(1-failure_rate_fullmesh(ec_total-1, p2, ec_parity))**pgs)) ** (n_hosts*n_drives));
}
// Wrapper for 4 above functions
function cluster_afr(config)
{
if (config.ec && config.afr_host)
{
return cluster_afr_pgs_ec_hosts(config);
}
else if (config.ec)
{
return cluster_afr_pgs_ec(config);
}
else if (config.afr_host)
{
return cluster_afr_pgs_hosts(config);
}
else
{
return cluster_afr_pgs(config);
}
}
function print_cluster_afr(config)
{
console.log(
`${config.n_hosts} nodes with ${config.n_drives} ${sprintf("%.1f", config.capacity/1000)}TB drives`+
`, capable to backfill at ${sprintf("%.1f", config.speed*1000)} MB/s, drive AFR ${sprintf("%.1f", config.afr_drive*100)}%`+
(config.afr_host ? `, host AFR ${sprintf("%.1f", config.afr_host*100)}%` : '')+
(config.ec ? `, EC ${config.ec[0]}+${config.ec[1]}` : `, ${config.replicas} replicas`)+
`, ${config.pgs||1} PG per OSD`+
(config.degraded_replacement ? `\n...and you don't let the rebalance finish before replacing drives` : '')
);
console.log('-> '+sprintf("%.7f%%", 100*cluster_afr(config))+'\n');
const disk_heal_fail = ((afr_drive+afr_host/n_drives)*disk_heal_time);
const host_heal_fail = ((afr_drive+afr_host/n_drives)*host_heal_time);
const disk_pg_fail = ec
? failure_rate_fullmesh(ec_data+ec_parity-1, disk_heal_fail, ec_parity)
: disk_heal_fail**(replicas-1);
const host_pg_fail = ec
? failure_rate_fullmesh(ec_data+ec_parity-1, host_heal_fail, ec_parity)
: host_heal_fail**(replicas-1);
return 1 - ((1 - afr_drive * (1-(1-disk_pg_fail)**pgs)) ** (n_hosts*n_drives))
* ((1 - afr_host * (1-(1-host_pg_fail)**host_pgs)) ** n_hosts);
}
/******** UTILITY ********/

27
main.js

@ -29,7 +29,9 @@ class Calc extends preact.Component
afr_host: st.afr_host/100,
capacity: st.capacity*1000,
speed: st.speed/1000,
ec: st.ec ? [ st.ec_data, st.ec_parity ] : null,
ec: st.ec,
ec_data: st.ec_data,
ec_parity: st.ec_parity,
replicas: st.replicas,
pgs: 50,
degraded_replacement: st.eager,
@ -66,13 +68,26 @@ class Calc extends preact.Component
format4 = (n) =>
{
let p = Math.abs(n-(n|0)), m = 10000;
while (n < 1 && p != 0 && p < 0.1)
if (n >= 1 || n <= -1)
return ''+(Math.round(n*10000)/10000);
if (n == 0)
return '0';
let s = '0.', i = 0, c = 0;
if (n < 0)
{
p = p*10;
m = m*10;
s = '-0.';
n = -n;
}
return Math.round(n*m)/m;
while (n && i < 4)
{
n = n*10;
s += (n|0);
c = c || (n|0);
n = n-(n|0);
if (c)
i++;
}
return s;
}
componentDidMount()

Loading…
Cancel
Save