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我正在爲MongoDB編寫一個維護腳本，它將按照計劃壓縮來自副本集的集合。迄今爲止，我所看到的腳本看起來不錯，可以完成它針對主節點和次節點所做的工作。然而，存在一個問題：MongoDB維護
使用MongoDB副本集的系統是一個高可用性Web隊列，它不斷被寫入和讀取。因此，即使調用rs.StepDown（）幾秒鐘的停機時間也絕對不可接受。有沒有一種方法可以安全降級數百個客戶端的沒有MongoException的主節點？
謝謝！
p.s.這裏是一個應該通過一個cron作業，在低負載時每月一次
// assuming we are a replica set ;-)
if(rs.isMaster().setName){
try {
//check if the script is run against a master
if(rs.isMaster().ismaster){ //if so, step down as master
print("Connected to a PRIMARY node")
print("Will try to step down as primary");
rs.stepDown();
// after stepdown connections are dropped. do an operation to cause reconnect:
rs.isMaster();
// now ready to go.
// wait for another node to become primary -- it may need data from us for the last
// small sliver of time, and if we are already compacting it cannot get it while the
// compaction is running.
var counter = 1;
while(1) {
var m = rs.isMaster();
if(m.ismaster) {
print("ERROR: no one took over during our stepDown duration. we are primary again!");
assert(false);
}
if(m.primary){ // someone else is, great
print("new master host is: "+m.primary);
break;
}
print("waiting "+counter+" seconds");
sleep(1000);
counter++;
}
}else{
print("Connected to a SECONDARY node");
print("Going into Recovery Mode and Compacting");
}
// someone else is primary, so we are ready to proceed with a compaction
print(" ");
print("Compacting...");
print("- queue");
printjson(db.runCommand({compact:"queue"}));
print(" ");
} catch(e) {
print(" ");
print("ACHTUNG! Exception:" + e);
print(" ");
}
}else{
print('This script works with replica sets only');
}