学习笔记一：压缩
2015年2月5日
上午 10:23
压缩命令
压缩文件的扩展名大多是*.tar、*.tar.gz、*.tgz、*.gz、*.Z、*.bz2
常见的压缩命令gzip与bzip2，其中bzip2压缩比gzip要好
tar可以用来进行文件打包，并可支持gzip和bzip2的压缩
压缩 tar -jvc -f filename.tar.bz2 /directory
查询 tar -jtv -f filename.tar.bz2
解压 tar -jxv -f filename.tar.bz2 -C /puorose/directory
Dump 命令可备份文件系统或单一目录
Dump 的备份若针对文件系统时，可进行0~9的level差异备份。其中level为0为完整备份
restore命令可以还原被dump构建的备份文件
要新建光盘刻录数据时，可通过mkisofs命令来构建
可通过cdrecord来写入CD或DVD刻录机
dd可备份完整的分区或磁盘，因为dd可读取硬盘的扇区表面数据
cpio为相当优秀的备份命令，不过必须要搭配类似find命令来读入预备份文件
测试演练
gzip与bzip2压缩
tar打包
使用gzip压缩格式并且排除log和bz压缩档
[[email protected] schema]$ tar -zcv -f schema_tar_test.tar.gz --exclude=/u03/schema/*.log --exclude=/u03/schema/*.bz /u03/schema
使用bzip2压缩格式并且排除log和gz压缩档
[[email protected] schema]$ tar -jcv -f schema_tar_test.tar.bz2 --exclude=/u03/schema/*.log --exclude=/u03/schema/*.gz /u03/schema
查看两者压缩比例
[[email protected] schema]$ du -sh schema_tar_test.tar.*
160K schema_tar_test.tar.bz2
260K schema_tar_test.tar.gz
dump备份文件系统
模拟一个文件盘符
[[email protected] u04]# dd if=/dev/zero of=/u04/loop_mount bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 8.35942 seconds, 128 MB/s
[[email protected] u04]# mkfs.ext3 /u04/loop_mount
[[email protected] u04]# mount -o loop /u04/loop_mount /u04/mount_loop
[[email protected] u04]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 9.7G 5.4G 3.9G 59% /
/dev/sda6 31G 1.9G 28G 7% /u02
/dev/sda5 30G 21G 7.1G 75% /u01
/dev/sda1 190M 23M 158M 13% /boot
tmpfs 1005M 0 1005M 0% /dev/shm
/dev/sdb 504G 263G 216G 55% /u03
/dev/sdc1 504G 312G 167G 66% /u04
/u04/loop_mount 1008M 34M 924M 4% /u04/mount_loop
创建dump备份目录
[[email protected] u04]# mkdir backup
[[email protected] u04]# dump -0 -j -f /u04/backup/dump.bak /u04/loop_mount
DUMP: Dumping /dev/sdc1 (/u04 (dir /loop_mount)) to /u04/backup/dump.bak
DUMP: Label: none
DUMP: Writing 10 Kilobyte records
DUMP: Compressing output at compression level 2 (bzlib)
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 1067027 blocks.
DUMP: Volume 1 started with block 1 at: Thu Feb 5 10:08:25 2015
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /u04/backup/dump.bak
DUMP: Volume 1 completed at: Thu Feb 5 10:09:01 2015
DUMP: Volume 1 took 0:00:36
DUMP: Volume 1 transfer rate: 156 kB/s
DUMP: Volume 1 1067020kB uncompressed, 5627kB compressed, 189.626:1
DUMP: 1067020 blocks (1042.01MB) on 1 volume(s)
DUMP: finished in 36 seconds, throughput 29639 kBytes/sec
DUMP: Date of this level 0 dump: Thu Feb 5 10:08:25 2015
DUMP: Date this dump completed: Thu Feb 5 10:09:01 2015
DUMP: Average transfer rate: 156 kB/s
DUMP: Wrote 1067020kB uncompressed, 5627kB compressed, 189.626:1
DUMP: DUMP IS DONE
[[email protected] u04]# ls -l /u04/backup/
total 5640
-rw-r--r-- 1 root root 5762814 Feb 5 10:09 dump.bak
[[email protected] u04]# du -sh /u04/backup/
5.6M /u04/backup/
测试加入文件至目录
[[email protected] u04]# cp ogg.tar.gz /u04/mount_loop/
[[email protected] u04]# du -sh /u04/mount_loop/
503M /u04/mount_loop/
[[email protected] u04]# dump -1 -j -f /u04/backup/dump.bak /u04/loop_mount
DUMP: Only level 0 dumps are allowed on a subdirectory (不是单一文件系统)
DUMP: The ENTIRE dump is aborted.
备份boot盘符测试
[[email protected] u04]# dump -0 -j -f /u04/backup/dump_boot.bak /dev/sda1
[[email protected] u04]# dump -1 -j -f /u04/backup/dump_boo01.bak /dev/sda1
DUMP: WARNING: There is no inferior level dump on this filesystem
DUMP: WARNING: Assuming a level 0 dump by default (boot目录也没差异备份吗？)
[[email protected] u04]# cd /u04/backup/
[[email protected] backup]# ls
dump.bak dump_boo01.bak dump_boot.bak
[[email protected] backup]# du -sh *
5.6M dump.bak
16M dump_boo01.bak
16M dump_boot.bak
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Database
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Ip
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Gzip
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Bzip2
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xxxxx
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xxx.xxx.xxx.xxx
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2015/3/22 10:22:00 ~2015/3/23 01:5600 3小時
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16GB
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2015/03/25 09:05~2015/03/26 00:56 16小時
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9.2GB
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