[BBLISA] Good way to recover Linux server

[Eddy Harvey]

There are several major problems I can see with using dd as a backup
tool --

- Because you are backing up the "free space" as well as the space
occupied by the files, your backup will take extra long time.
- You cannot do incremental backups.
- Because you are backing up a system that is currently booted and
operating, you are likely to miss important data that isn't always
written to disk.  For example, if you run a mysql server, the updates to
the data in the database happen in realtime, yet the database file as
written to disk is not necessarily usable at all, let alone up-to-date.
- You are required to restore onto a disk with the same geometry, and it
is often nice to alleviate yourself from this restriction.

----------------------------------------
There is one, very common oversight by people doing backups of their
system --

Simply using tar, or dd, or dump is not necessarily good enough.  You
have to understand what applications are running, and follow that
application's recommended backup procedure.  The best example I can
think of is mysql.  Before backing up your system, if you run mysql, I
would suggest running mysqldump to put the latest data into a file, and
then run dump to backup the files.  When you restore, you would use
"restore" and then when you start the mysqld, you would need to
re-import the mysqldump file.

----------------------------------------
Sharon, I hate to say it (because it is a lot of work) but I think the
best backup method is this --

- First backup your applications to file, if applicable for the
applications that you run.
- Then backup the FS using dump

When you need to restore,

- Boot a rescue CD or install a minimal partition of a secondary linux
- Repartition & format
- Mount the destination partition and Run restore
- Install the bootloader
- Boot the OS that you are restoring.
- Restore the applications, if applicable.




-----Original Message-----
From: bblisa-bounces at bblisa.org [mailto:bblisa-bounces at bblisa.org] On
Behalf Of Tom Metro
Sent: Wednesday, August 10, 2005 7:04 PM
To: L-bblisa
Subject: Re: [BBLISA] Good way to recover Linux server


Theo Van Dinter wrote:
> snagao wrote:
>> I know Linux doesn't have anything equivalent to AIX's mksysb 
>> command,  but can someone please recommend a tool or method for me to

>> back up the OS and recover it quickly for DR testing?
> 
> I don't know of a "all in one" utility off the top of my head, I've 
> always either done dump or more likely tar of the files.  Then on bare

> metal recovery, you just boot into a rescue CD, make the partitions 
> and filesystems, untar, reinstall the boot loader, reboot.

Instead of tar or dump, you can use dd to image the entire drive, 
including its partition table and boot sector, or an individual 
partition. Similarly Partimage (http://partimage.org/) will let you save

a partition to a file with the added benefit that it intelligently skips

over unused space.

As above, you'll need to bootable rescue CD, such as SystemRescueCd 
(http://www.sysresccd.org/), in order to restore partitions on an 
unbootable system.

Try reposting your query on the BLU (www.blu.org) discuss list, as 
you'll find a larger population of Linux users there.

  -Tom

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