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错误的潜在原因

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错误的潜在原因

您好，我对 ZFS 快照备份脚本有疑问：

基本上，脚本的分解如下：

### START OF SCRIPT
# These variables are named first because they are nested in other variables.
snap_prefix=snap
retention=10

# Full paths to these utilities are needed when running the script from cron.
#date=/usr/bin/date
GDATE="/opt/csw/bin/gdate"
grep=/usr/bin/grep
#mbuffer=/usr/local/bin/mbuffer
sed=/usr/bin/sed
sort=/usr/bin/sort   
xargs=/usr/bin/xargs
zfs=/sbin/zfs
src_0="ServerStoreR10SSD"

dst_0="zpoolRZ5SATA3/backuppool4/ServerStoreR10SSD"
host="root@hostbk"
today="$snap_prefix-`date +%Y%m%d`"
#yesterday="$snap_prefix-`date -v -1d +%Y%m%d`"
yesterday=$snap_prefix-`$GDATE -d "-1 day" +"%Y%m%d"`
snap_today="$src_0@$today"
snap_yesterday="$src_0@$yesterday"
snap_old=`$zfs list -t snapshot -o name | $grep "$src_0@$snap_prefix*" | $sort -r | $sed 1,${retention}d | $sort | $xargs -n 1`
log=/root/bin/zfsreplication/cronlog/ServerStoreR10SSD.txt
# Create a blank line between the previous log entry and this one.
echo >> $log

# Print the name of the script.
echo "zfsrep_ServerStoreR10SSD.sh" >> $log

# Print the current date/time.
$date >> $log

echo >> $log

# Look for today's snapshot and, if not found, create it.
if $zfs list -H -o name -t snapshot | $sort | $grep "$snap_today$" > /dev/null
then
        echo "Today's snapshot '$snap_today' already exists." >> $log
        # Uncomment if you want the script to exit when it does not create today's snapshot:
        #exit 1
else
        echo "Taking today's snapshot: $snap_today" >> $log
        $zfs snapshot -r $snap_today >> $log 2>&1
fi

echo >> $log

# Look for yesterday snapshot and, if found, perform incremental replication, else print error message.
if $zfs list -H -o name -t snapshot | $sort | $grep "$snap_yesterday$" > /dev/null
then
        echo "Yesterday's snapshot '$snap_yesterday' exists. Proceeding with replication..." >> $log
        $zfs send -R -i $snap_yesterday $snap_today | ssh $host $zfs receive -vudF $dst_0 >> $log 2>&1
        #For use in local snapshots
        #$zfs send -R -i $snap_yesterday $snap_today | $zfs receive -vudF $dst_0 >> $log 2>&1
        echo >> $log
        echo "Replication complete." >> $log
else
        echo "Error: Replication not completed. Missing yesterday's snapshot." >> $log
fi

echo >> $log

 # Remove snapshot(s) older than the value assigned to $retention.
 echo "Attempting to destroy old snapshots..." >> $log

  if [ -n "$snap_old" ]
  then
    echo "Destroying the following old snapshots:" >> $log
    echo "$snap_old" >> $log
    $zfs list -t snapshot -o name | $grep "$src_0@$snap_prefix*" | $sort -r 
| $sed 1,${retention}d | $sort | $xargs -n 1 $zfs destroy -r >> $log 2>&1
else
echo "Could not find any snapshots to destroy."     >> $log
fi

# Mark the end of the script with a delimiter.
echo "**********" >> $log

# END OF SCRIPT
~

日志显示以下内容

昨天的快照“ServerStoreR10SSD@snap-20170419”已存在。继续复制...无法接收：指定的 fs（zpoolRZ5SATA3/backuppool4/ServerStoreR10SSD）不存在尝试销毁 zpoolRZ5SATA3/backuppool4/ServerStoreR10SSD 失败 - 尝试将 zpoolRZ5SATA3/backuppool4/ServerStoreR10SSD 重命名为 zpoolRZ5SATA3/backuppool4/ServerStoreR10SSDrecv-5424-1 无法打开“zpoolRZ5SATA3/backuppool4/ServerStoreR10SSD”：数据集不存在

在我停电之前，脚本一直运行成功。主要问题是每次运行增量部分时，接收 zfs 池都会重命名为奇怪的名称，如“..recv-5424-1”，因此无法打开目标池，备份失败...

有什么建议吗？

答案1

您的脚本没有显示rename或destroy操作，并且我们不知道源和目标快照，因此这个答案是可以应用于您的情况的通用建议：

错误的潜在原因

要使增量 ZFSsend/recv正常工作，您始终需要在源端和目标端拥有快照N和。然后，您将和之间的增量（差异）发送到目标端，在那里它将成为。之后，您可以在源端删除并重复该过程。N-1N-1N-1NNN-1

立即修复

如果您的某个快照与此系统不匹配（例如因为它已被删除或重命名），则有两种可能的方法来更正它：

  1. 删除远程端的所有数据，然后执行完整/初始/正常发送/接收。这需要更多时间，但您不需要进行太多故障排除。
  2. 如果可能的话，找出到底是什么问题，并手动纠正所有问题（如果您已经删除了所需的快照，则可能无法实现）。

针对未来问题的改进

除此之外，您还应该检查脚本流程，看看这个错误是如何出现的。将其重构为较小的函数（如、、send_initial等）会有所帮助，这样您就可以更清楚地了解什么时候会发生什么。然后绘制一个状态机图 (DFA)，其中包含可能的分支和流程，并查看每个状态变化：如果发生错误（网络丢失、断电、用户取消脚本、权限被拒绝等），会发生什么，以及如何缓解它？send_diffcreate_snapdelete_snap

如果工作量太大，您也可以使用已经解决这些问题的现有解决方案。对于其中一些，请查看这个问题来自两周前。

答案2

在我的源 zfs 列表中

ServerStoreR10SSD                       380G   321G  44.9K  /ServerStoreR10SSD
ServerStoreR10SSD/DataStore2R10SSD      380G   321G   296G  /ServerStoreR10SSD/DataStore2R10SSD

在我的来源上，快照是：

ServerStoreR10SSD@snap-20170411                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170412                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170413                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170414                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170415                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170416                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170417                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170418                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170419                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170420                          0      -  44.9K  -
ServerStoreR10SSD@snap-20170421                          0      -  44.9K  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170411     8.77G      -   295G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170412     3.95G      -   295G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170413     3.11G      -   295G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170414     2.99G      -   295G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170415     5.61G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170416     3.31G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170417     2.76G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170418     3.74G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170419     3.65G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170420     2.72G      -   296G  -
ServerStoreR10SSD/DataStore2R10SSD@snap-20170421     2.27G      -   296G  -

我的目标上的 zfs 列表

zpoolRZ5SATA3/backuppool3                                                1.19T  1.77T   202K  /zpoolRZ5SATA3/backuppool3
zpoolRZ5SATA3/backuppool3/DataStoreR10

在我的目的地上列出快照：

zpoolRZ5SATA3/backuppool4@moving                                                        139K      -   202K  -
zpoolRZ5SATA3/backuppool4/ServerStoreR10SSDrecv-9540-1/DataStore2R10SSD@snap-20170418  11.8G      -   296G  -
zpoolRZ5SATA3/backuppool4/ServerStoreR10SSDrecv-9540-1/DataStore2R10SSD@snap-20170419  3.67G      -   296G  -
zpoolRZ5SATA3/backuppool4/ServerStoreR10SSDrecv-9540-1/DataStore2R10SSD@snap-20170420      0      -   296G  -

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