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Do not crash when optimising PGs in an undersized cluster

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This commit is contained in:
Vitaliy Filippov
2020-05-15 01:29:15 +03:00
parent b467d0559f
commit 7bda66b866
2 changed files with 114 additions and 17 deletions
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lp/lp-optimizer.js
+43 -17
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@@ -2,6 +2,8 @@
const child_process = require('child_process');
const NO_OSD = 'Z';
async function lp_solve(text)
{
const cp = child_process.spawn('lp_solve');
@@ -49,7 +51,7 @@ async function optimize_initial(osd_tree, pg_count, max_combinations)
{
max_combinations = max_combinations || 10000;
const all_weights = Object.assign({}, ...Object.values(osd_tree));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
let all_pgs = all_combinations(osd_tree, null, true);
if (all_pgs.length > max_combinations)
{
@@ -65,12 +67,16 @@ async function optimize_initial(osd_tree, pg_count, max_combinations)
pg_per_osd[osd].push("pg_"+pg.join("_"));
}
}
const pg_size = Math.min(Object.keys(osd_tree).length, 3);
let lp = '';
lp += "max: "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(' + ')+";\n";
for (const osd in pg_per_osd)
{
let osd_pg_count = all_weights[osd]*3/total_weight*pg_count;
lp += pg_per_osd[osd].join(' + ')+' <= '+osd_pg_count+';\n';
if (osd !== NO_OSD)
{
let osd_pg_count = all_weights[osd]/total_weight*pg_size*pg_count;
lp += pg_per_osd[osd].join(' + ')+' <= '+osd_pg_count+';\n';
}
}
for (const pg of all_pgs)
{
@@ -78,14 +84,18 @@ async function optimize_initial(osd_tree, pg_count, max_combinations)
}
lp += "sec "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(', ')+";\n";
const lp_result = await lp_solve(lp);
if (!lp_result)
{
throw new Error('Problem is infeasible or unbounded - is it a bug?');
}
const int_pgs = make_int_pgs(lp_result.vars, pg_count);
const eff = pg_list_space_efficiency(int_pgs, all_weights);
return { score: lp_result.score, weights: lp_result.vars, int_pgs, space: eff, total_space: total_weight };
return { score: lp_result.score, weights: lp_result.vars, int_pgs, space: eff*pg_size, total_space: total_weight };
}
function make_int_pgs(weights, pg_count)
{
const total_weight = Object.values(weights).reduce((a, c) => Number(a) + Number(c));
const total_weight = Object.values(weights).reduce((a, c) => Number(a) + Number(c), 0);
let int_pgs = [];
let pg_left = pg_count;
let weight_left = total_weight;
@@ -106,6 +116,7 @@ function make_int_pgs(weights, pg_count)
async function optimize_change(prev_int_pgs, osd_tree, max_combinations)
{
max_combinations = max_combinations || 10000;
const pg_size = Math.min(Object.keys(osd_tree).length, 3);
const pg_count = prev_int_pgs.length;
const prev_weights = {};
const prev_pg_per_osd = {};
@@ -164,7 +175,7 @@ async function optimize_change(prev_int_pgs, osd_tree, max_combinations)
// Calculate total weight - old PG weights
const all_pg_names = all_pgs.map(pg => 'pg_'+pg.join('_'));
const all_weights = Object.assign({}, ...Object.values(osd_tree));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
// Generate the LP problem
let lp = '';
lp += 'max: '+all_pg_names.map(pg_name => (
@@ -172,10 +183,13 @@ async function optimize_change(prev_int_pgs, osd_tree, max_combinations)
)).join(' + ')+';\n';
for (const osd in pg_per_osd)
{
const osd_sum = (pg_per_osd[osd]||[]).map(pg_name => prev_weights[pg_name] ? `add_${pg_name} - del_${pg_name}` : pg_name).join(' + ');
const rm_osd_pg_count = (prev_pg_per_osd[osd]||[]).filter(old_pg_name => move_weights[old_pg_name]).length;
let osd_pg_count = all_weights[osd]*3/total_weight*pg_count - rm_osd_pg_count;
lp += osd_sum + ' <= ' + osd_pg_count + ';\n';
if (osd !== NO_OSD)
{
const osd_sum = (pg_per_osd[osd]||[]).map(pg_name => prev_weights[pg_name] ? `add_${pg_name} - del_${pg_name}` : pg_name).join(' + ');
const rm_osd_pg_count = (prev_pg_per_osd[osd]||[]).filter(old_pg_name => move_weights[old_pg_name]).length;
let osd_pg_count = all_weights[osd]*3/total_weight*pg_count - rm_osd_pg_count;
lp += osd_sum + ' <= ' + osd_pg_count + ';\n';
}
}
let pg_vars = [];
for (const pg_name of all_pg_names)
@@ -259,7 +273,7 @@ async function optimize_change(prev_int_pgs, osd_tree, max_combinations)
int_pgs: new_pgs,
differs,
osd_differs,
space: pg_list_space_efficiency(new_pgs, all_weights),
space: pg_size * pg_list_space_efficiency(new_pgs, all_weights),
total_space: total_weight,
};
}
@@ -286,8 +300,8 @@ function print_change_stats(retval, detailed)
);
}
console.log(
"Total space (raw): "+Math.round(retval.space*3*100)/100+" TB, space efficiency: "+
Math.round(retval.space*3/retval.total_space*10000)/100+" %"
"Total space (raw): "+Math.round(retval.space*100)/100+" TB, space efficiency: "+
Math.round(retval.space/(retval.total_space||1)*10000)/100+" %"
);
}
@@ -377,10 +391,17 @@ function extract_osds(osd_tree, levels, osd_level, osds = {})
return osds;
}
// FIXME: support different pg_sizes, not just 3
// osd_tree = { failure_domain1: { osd1: size1, ... }, ... }
function all_combinations(osd_tree, count, ordered)
{
const hosts = Object.keys(osd_tree).sort();
const osds = Object.keys(osd_tree).reduce((a, c) => { a[c] = Object.keys(osd_tree[c]).sort(); return a; }, {});
while (hosts.length < 3)
{
osds[NO_OSD] = [ NO_OSD ];
hosts.push(NO_OSD);
}
let host_idx = [ 0, 1, 2 ];
let osd_idx = [ 0, 0, 0 ];
const r = [];
@@ -470,16 +491,21 @@ function pg_per_osd_space_efficiency(per_osd, pg_count, osd_sizes)
let space;
for (let osd in per_osd)
{
const space_estimate = osd_sizes[osd] * pg_count / per_osd[osd];
if (space == null || space > space_estimate)
if (osd in osd_sizes)
{
space = space_estimate;
const space_estimate = osd_sizes[osd] * pg_count / per_osd[osd];
if (space == null || space > space_estimate)
{
space = space_estimate;
}
}
}
return space;
return space == null ? 0 : space;
}
module.exports = {
NO_OSD,
optimize_initial,
optimize_change,
print_change_stats,