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--- bare_metal_linux_backups_with_rdx [2019/02/15 16:15] – [Using Dump for Backups] sgriggs
+++ bare_metal_linux_backups_with_rdx [2019/02/15 16:30] (current) – [Using Tar for system backups] sgriggs
@@ Line 128: / Line 128: @@
 </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>