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使用 tar/gz 将目录存档到多个位置并省略额外的副本

tag-icon • tag-icon bash tar gzip archive
使用 tar/gz 将目录存档到多个位置并省略额外的副本

我有一个简单的备份脚本，它还会将本地数据创建到外部 USB 设备的 tar/gzip 存档，然后将该存档复制到第二个 USB 设备。

例如：

usb1="/mnt/usbone"
usb2="/mnt/usbtwo"
source="/home/user"

tar cfz ${usb1}/source.tar.gz ${source}
cp -ar ${usb1}/source.tar.gz ${usb2}

这似乎可以优化为tar在两个驱动器上创建副本，而不是创建一个存档，然后再复制。生成的存档相当小 (<1GB)。我知道这不是安全的备份方法。

编辑：我已经快速测试了 Archemar 的解决方案并比较了这些方法。为了更好地衡量，我还使用 测试了最初的方法rsync。查看结果time（不是 bash 时间，/usr/bin/time）以及我用来测试它的脚本。

源是用创建的dd if=/dev/urandom bs=1M count=1024 of=/tmp/random.blob。主机是通过 microSD 卡运行的 Raspberry Pi 3B，安装的目标是 USB 2.0 闪存驱动器（${a}和${b}）。

a.sh（tar 和 cp）：

tar cfz ${a}/r1.tar.gz ${s}
cp -ar ${a}/r1.tar.gz ${b}/r1.tar.gz

b.sh（tar 和 tee）：

tar cfz - ${s} | tee ${a}/r2.tar.gz > ${b}/r2.tar.gz

c.sh（tar 和 rsync）：

tar cfz ${a}/r3.tar.gz ${s}
rsync -aW ${a}/r3.tar.gz ${b}/r3.tar.gz

结果：

# /usr/bin/time -v bash a.sh 
        Command being timed: "bash a.sh"
        User time (seconds): 218.71
        System time (seconds): 28.33
        Percent of CPU this job got: 68%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 6:03.13
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 2480
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 41
        Minor (reclaiming a frame) page faults: 1250
        Voluntary context switches: 45519
        Involuntary context switches: 25576
        Swaps: 0
        File system inputs: 3668157
        File system outputs: 4197336
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

        
# /usr/bin/time -v bash b.sh 
        Command being timed: "bash b.sh"
        User time (seconds): 221.64
        System time (seconds): 28.62
        Percent of CPU this job got: 85%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 4:53.98
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 2536
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 31
        Minor (reclaiming a frame) page faults: 1162
        Voluntary context switches: 68310
        Involuntary context switches: 35582
        Swaps: 0
        File system inputs: 2101321
        File system outputs: 4197832
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

        
# /usr/bin/time -v bash c.sh 
        Command being timed: "bash c.sh"
        User time (seconds): 235.24
        System time (seconds): 35.01
        Percent of CPU this job got: 74%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 6:04.03
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 2652
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 40
        Minor (reclaiming a frame) page faults: 2310
        Voluntary context switches: 65402
        Involuntary context switches: 45179
        Swaps: 0
        File system inputs: 4200957
        File system outputs: 4197496
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0

令我惊讶的是，结果并没有那么明显。File system inputs: 2101321不过，使用 tar/tee 方法要低很多，我希望这对 SD 卡的寿命有好处。

答案1

你可以使用tee命令

usb1="/mnt/usbone"
usb2="/mnt/usbtwo"
source="/home/user"

tar -cz -f - "${source}" | tee "${usb2}/source.tar.gz" > "${usb1}/source.tar.gz"

在哪里

  • -f -告诉tar使用 stdout 作为备份文件。
  • tee "${usb2}/source.tar.gz" 将把标准输入复制到指定的文件和标准输出。
  • > "${usb1}/source.tar.gz"将重定向标准输出tee到文件。

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