linux – 如何并行化scp命令？

我需要将文件从machineB和machineC scp到machineA.我从machineA运行我的下面的 shell脚本.我已正确设置了ssh密钥.

如果文件不在machineB中,那么它应该在machineC中.我需要将所有PARTITION1和PARTITION2文件移动到machineA各自的文件夹中,如下面的shell脚本所示 –

#!/bin/bash

readonly PRIMARY=/export/home/david/dist/primary
readonly SECONDARY=/export/home/david/dist/secondary
readonly FILERS_LOCATION=(machineB machineC)
readonly MAPPED_LOCATION=/bat/data/snapshot
PARTITION1=(0 3 5 7 9)
PARTITION2=(1 2 4 6 8)

dir1=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[0]} ls -dt1 "$MAPPED_LOCATION"/[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9] | head -n1)
dir2=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[1]} ls -dt1 "$MAPPED_LOCATION"/[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9] | head -n1)

length1=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[0]} "ls '$dir1' | wc -l")
length2=$(ssh -o "StrictHostKeyChecking no" david@${FILERS_LOCATION[1]} "ls '$dir2' | wc -l")

if [ "$dir1" = "$dir2" ] && [ "$length1" -gt 0 ] && [ "$length2" -gt 0 ]
then
    rm -r $PRIMARY/*
    rm -r $SECONDARY/*
    for el in "${PARTITION1[@]}"
    do
        scp david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/. || scp david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/.
    done
    for sl in "${PARTITION2[@]}"
    do    
        scp david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/. || scp david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$sl"_200003_5.data $SECONDARY/.
    done
fi

目前,我在PARTITION1和PARTITION2中有5个文件,但一般来说它将有大约420个文件,这意味着它将逐个移动文件,我认为这可能很慢.有没有办法加快这个过程？

我正在运行Ubuntu 12.04

解决方法

并行化SCP会适得其反,除非双方都使用SSD. SCP最慢的部分是网络枯萎,在这种情况下,并行化根本不会有任何帮助,或者任何一方的磁盘,你会因并行化而变得更糟：寻找时间会杀了你.

你说machineA在SSD上,所以每台机器的并行化就足够了.最简单的方法是将第一个forloop包装在子shell中并将其背景化.

( for el in "${PARTITION1[@]}"
do
    scp david@${FILERS_LOCATION[0]}:$dir1/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/. || scp david@${FILERS_LOCATION[1]}:$dir2/t1_weekly_1680_"$el"_200003_5.data $PRIMARY/.
done ) &