目标：把一台linux机上mongodb的数据定时备份到另一台机上：
过程：
一开始打算使用mongoexport和mongoimport，但是总是会报“\x00”字符串不能识别的问题，后来就改成了mongodump和mongorestart，成功实现目标。
（\x00的问题还在寻找解决办法）；
脚本代码：
#获取系统时间并转换成毫秒数
current=`date "+%Y-%m-%d %H:%M:%S"`;
timeStamp=`date -d "$current" +%s`;
#当前时间的毫秒数
currentTimeStamp=$((timeStamp*1000));
#一个小时前这个时候的毫秒数
yestodayTimeStamp=$((currentTimeStamp-43*60*60*1000));
echo $current;
echo $timeStamp;
echo $currentTimeStamp;
echo $yestodayTimeStamp;
echo "File not exist!dump `date "+%Y-%m-%d %H:%M:%S"` $currentTimeStamp $yestodayTimeStamp" >>/home/admin/testlog.log
#备份新产生表
/home/admin/mongodb305/mongodb305/bin/mongodump --port 47017 -u admin -p admin -d admin -c alarm -q '{"recTime":{$gte:'$yestodayTimeStamp',$lt:'$currentTimeStamp'}}' -o /home/admin/dumptest;
/home/admin/mongodb305/mongodb305/bin/mongodump --port 47017 -u admin -p admin -d admin -c filtering_alarm -q '{"recTime":{$gte:'$yestodayTimeStamp',$lt:'$currentTimeStamp'}}' -o /home/admin/dumptest;
/home/admin/mongodb305/mongodb305/bin/mongodump --port 47017 -u admin -p admin -d admin -c combine_alarm -q '{"recTime":{$gte:'$yestodayTimeStamp',$lt:'$currentTimeStamp'}}' -o /home/admin/dumptest;
/home/admin/mongodb305/mongodb305/bin/mongodump --port 47017 -u admin -p admin -d admin -c processed_alarm -q '{"recTime":{$gte:'$yestodayTimeStamp',$lt:'$currentTimeStamp'}}' -o /home/admin/dumptest
/home/admin/mongodb305/mongodb305/bin/mongorestore -h 192.168.0.213 --port 27017 -u admin -p admin -d admin -c alarm --keepIndexVersion --maintainInsertionOrder /home/admin/dumptest/admin/alarm.bson;
/home/admin/mongodb305/mongodb305/bin/mongorestore -h 192.168.0.213 --port 27017 -u admin -p admin -d admin -c filtering_alarm --keepIndexVersion --maintainInsertionOrder /home/admin/dumptest/admin/filtering_alarm.bson;
/home/admin/mongodb305/mongodb305/bin/mongorestore -h 192.168.0.213 --port 27017 -u admin -p admin -d admin -c combine_alarm --keepIndexVersion --maintainInsertionOrder /home/admin/dumptest/admin/combine_alarm.bson;
/home/admin/mongodb305/mongodb305/bin/mongorestore -h 192.168.0.213 --port 27017 -u admin -p admin -d admin -c processed_alarm --keepIndexVersion --maintainInsertionOrder /home/admin/dumptest/admin/processed_alarm.bson
39 10 * * * root /home/admin/dumptest2.sh
备份之后根据条件查看两个mongodb中的数据一致，备份成功。
