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Raw Device Backup

Created: 10 May 2013 | 5 comments
Twinkle Sapra's picture

We have to perform an activity for one of file system to increase the inode value which requires format of filesystem with new inode value.Prior to activity we have to backup the mount point. Now the problem is that this mount point is having millons of files and standard backup is taking very long time.  We can't use the Flash backup as it is Linux machine using LVM and Flash backup is not supported in this scenario.

I tried taking backup using RAW device and backup is perfectly doing fine with very good speed. But I am not sure, when I will do the restore, will the inode or other file system attribute will change or not.

Another option to create a new file system and copy content of source to target file system with dd command. Here I am also not sure, will it chage the file system property doing restore back.

Any other option if above didn't work ?

Operating Systems:

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Nicolai's picture

I would not recommedn to use the backup system to copy the files. 

Copy file from the source to the destination file system with a tool like rsync. rsync can do "catch up" and "mirroring" in case somthing interrup the copy process. Permissions are taken into account as well with the right command line options.


Assumption is the mother of all mess ups.

If this post answered your'e qustion -  Please mark as a soloution.

Twinkle Sapra's picture

There are millions of files. Rsyc will take number of days to copy.

What if, we take backup of partition (/dev/mapper/VolGroup01-u01)  and restore back to the same partition (which will be formatted with new inode value after backup). Will restore change the old Inode or file system setting?

revarooo's picture

Try it on a test system!

Marianne's picture

I cannot comment on how restores will affect inodes.

Just please review requirements for raw backups and restore carefully. 

See UNIX raw partitions in NBU Admin Guide I

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

Twinkle Sapra's picture

Testing steps performed

1. Backup performed one of partitions /dev/mapper/VolGroup01-tmp

2. Create same type and size of mapper device on backup server /dev/mapper/VolGroup01-tmp with new "i-node" value.

3. Restore performed on backup server to /dev/mapper/VolGroup01-tmp.

4. Old i-node values replaced.

Nutshell:- It didn't work.

Still looking of alternate solution except "rsync".