Solved

backing up active filesystems safely

Posted on 1998-08-04
2
266 Views
Last Modified: 2013-11-15
I'm using Redhat Linux 5.0 with a scsi 4mm tape drive.
I don't have any problems writing to or reading from the tape.
For example:
  To backup I can type:  tar -czvSf /dev/tape /home/mag
  To restore I can type:  cat /dev/tape >foo.tar.gz
    then I can type: gzip -d foo.tar.gz
    then I can type: tar xvf foo.tar
    and I'm back in business.

I have heard that tar is not a good backup tool to use if the filesystem is changing.

Is it any part of the filesystem that corrupts the backup?  Or is it only a problem if the file being backed up changes?

Is their a failsafe method of backing up the files to a tape drive?  dump?  zip?
0
Comment
Question by:mag062397
2 Comments
 
LVL 2

Expert Comment

by:JYoungman
ID: 1637706
If the data being backed up changes during the backup,
you may find that the data on the tape for a given file does not correspond to what was the contents of the file at *any* time; it may be half-and-half or something like that.

Common wisdom has it that dump(1) is more resistant to these problems, but I haven't read the source so I'm not sure.

Personally, I do backups with tar, but duiring the night when those filesystems are not being used.

Filesystem snapshots will appear in the 2.3 or 2.5 Linux kernel series, I think, so in the end the problem will be solved the right way.

0
 
LVL 4

Accepted Solution

by:
jlms earned 70 total points
ID: 1637707
The problem of "live" filesystems is one of the filesystem you are using. Only a few recent filesystems allow you to do that, but Linux does not have them implemented (Veritas fs for example).

   So to be 100% in the safe side, you should back up filesystems that are not been used. Utilities like dump allow you to do so with the filesystem unmounted, which guarantees the fiabilty of what goes to the tape.
0

Featured Post

Complete VMware vSphere® ESX(i) & Hyper-V Backup

Capture your entire system, including the host, with patented disk imaging integrated with VMware VADP / Microsoft VSS and RCT. RTOs is as low as 15 seconds with Acronis Active Restore™. You can enjoy unlimited P2V/V2V migrations from any source (even from a different hypervisor)

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

If your app took Google’s lash recently, here are the 5 most likely reasons.
Developer portfolios can be a bit of an enigma—how do you present yourself to employers without burying them in lines of code?  A modern portfolio is more than just work samples, it’s also a statement of how you work.
This video demonstrates how to use each tool, their shortcuts, where and when to use them, and how to use the keyboard to improve workflow.
The viewer will learn how to successfully create a multiboot device using the SARDU utility on Windows 7. Start the SARDU utility: Change the image directory to wherever you store your ISOs, this will prevent you from having 2 copies of an ISO wit…

863 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

22 Experts available now in Live!

Get 1:1 Help Now