User Tools

Site Tools


bare_metal_linux_backups_with_rdx

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Last revision Both sides next revision
bare_metal_linux_backups_with_rdx [2019/02/15 16:15]
sgriggs [Using Dump for Backups]
bare_metal_linux_backups_with_rdx [2019/02/15 16:29]
sgriggs
Line 128: Line 128:
 </​code>​ </​code>​
  
 +==== Using Tar for system backups ====
  
 +Tar (and by extension other file archivers like **pax** and **cpio**) can also work for system backups. Here are the pros and cons. 
 +
 +Advantages of using **tar** for backups:
 +  * Tar is fast
 +  * Tar is broadly compatible. You'll be able to dig into the archive with many tools on many OSes. 
 +  * Tar doesn'​t implement compression,​ leaving you free to compress tar files with anything you want
 +  * It can go direct to a tape or disk device like **dump** but it also to a file.
 +
 +Drawbacks of using **tar** for system backups:
 +  * Tar doesn'​t do estimates of when it'll complete. It just goes and goes sequentially until done. 
 +  * Tar isn't as pedantic about weird files like named-pipes or FIFO files. It might not archive them as well as **dump** but most people don't care and don't need that to work anyway as most of those types of files are created dynamically. ​
 +  * By default, tar won't care if it crosses a filesystem boundry. This can cause problems and I recommend you use the **--mount** ​ or **--xdev** flags when doing system backups to avoid this issue. Backup the filesystems separately or use exclude lists
 +  * Tar isn't smart enough to automatically avoid synthetic filesytems like **/proc** or **/sys**, or  ​
 +
 +=== Tar examples ===
 +
 +For doing system backups there are two things I recommend you do that are not tar's default behavior. ​
 +  ​
 +  - Do not let it cross file systems.
 +  - Do not let it backup in-memory filesystems like /proc
 +
 +So, in my example, let's say I have three critical filesystems that are part of my OS build. They are **/**, **/usr**, and **/home**. I want to dump them to an RDX with a filesystem because I don't want to fiddle with any direct-to-device backups. Here goes. 
 +
 +<​code>​
 +## Double check my filesystems so I know what I'm dumping
 +$ mount
 +
 +## Find my RDX Drive by exploring the drives on the system
 +fdisk -l
 +ls /​dev/​disk/​by-id
 +
 +## Put a partition on the RDX drive, in this case /dev/sdb
 +fdisk /dev/sdb
 +## If the disk has partitions you want to delete, do so with "​d"​
 +## Then use "​n"​ for new partition and take the defaults. It defaults to Linux
 +## then hit "​w"​ to save/write and quit from fdisk. ​
 +
 +## Put a filesystem on the partition
 +mkfs /dev/sdb1
 +
 +## Mount the RDX filesystem on the /backup directory
 +mount /dev/sdb1 /backup
 +
 +## Perform the tar backups one FS at a time using GZIP compression
 +tar -c --one-file-system -vzf /​backup/​root_backup.tar.gz /
 +tar -c --one-file-system -vzf /​backup/​usr_backup.tar.gz /usr
 +tar -c --one-file-system -vzf /​backup/​home_backup.tar.gz /home
 +
 +</​code>​
bare_metal_linux_backups_with_rdx.txt · Last modified: 2019/02/15 16:30 by sgriggs