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Backups

Overview

Non-commercial Backup Programs for Linux

Commercial backup programs for Linux

Pro's and cons of back media

Overview

I don't know how many times I can tell people, but it never ceases to amaze me how often people are surprised by the fact that if they do not backup their data it will be gone, if the drive suffers a head crash on them or they hit 'delete' without thinking. Always backup your system, even if it's just the config files, you'll save yourself time and money in the long run.

To backup your data under Linux there are many solutions, all with various pro's and con's. There are also several industrial strength backup programs, the better ones support network backups which are a definite plus in a large non-homogenous environment.

Non-commercial backup programs for Linux

Tar and Gzip

Oldies but still goldies, tar and gzip. Why? Because like vi you can darn near bet the farm on the fact that any UNIX system will have tar and gzip. They may be slow, klunky and starting to show their age, but it's a universal tool that will get the job done. I find with Linux the installation of a typical system takes 15-30 minutes depending on the speed of the network/cdrom, configuration another 5-15 (assuming I have backups or it is very simple) and data restoration takes as long as it takes (definitely not something you should rush). Good example: I recently backed up a server and then proceeded to blow the filesystem away (and remove 2 physical HD's that I no longer needed), I then installed Red Hat 5.2, and reconfigured all 3 network cards, Apache (for about 10 virtual sites), Bind and several other services in about 15 minutes. If I had done it from scratch it would have taken me several hours. Simply:

tar -cvf archive-name.tar dir1 dir2 dir3....

to create the tarball of all your favorite files (typically /etc, /var/spool/mail/, /var/log/, /home, and any other user/system data), followed by a:
gzip -9 archive-name.tar
to compress it as much as possible (granted harddrive space is cheaper then a politicians promise but compressing it makes it easier to move around). You might want to use bzip, which is quite a bit better then gzip at compressing text, but it is quite a bit slower. I typically then make a copy of the archive on a remote server, either by ftping it or emailing it as an attachment if it's not to big (e.g. the backup of a typical firewall is around 100k or so of config files).

rsync

rsync is an ieal way to move data between servers. It is very effecient for maintaining large directory trees in synch (not real time mind you), and is relatively easy to configure and secure. rsync does not encrypt the data however so you should use something like IPSec if the data is sensitive. rsync is covered here.

Amanda

Amanda is a client/server based network backup programs with support for most unices and Windows (via SAMBA). Amanda is BSD style licensed and available from: http://www.amanda.org/.

afbackup

Afbackup is another client/server with a generally GPL license with one minor exception, development of the server portion on Windows is forbidden. Afbackup has server support for Linux, HP-UX and Solaris, and has clients for that and windows. You can download it at:
ftp://ftp.zn-gmbh.com/pub/linux/.

Burt

Burt is a Tcl/Tk based set of extensions that allow for easy backups of Unix workstations, this allows it to run on pretty much any system. Burt is a client/server architecture and appears pretty scalable, it is available at: http://www.cs.wisc.edu/~jmelski/burt/.

Commercial backup programs for linux

 

BRU

BRU (Backup and Restore Utility), has been in the Linux world since as long as Linux Journal (they have had ads in there since the beginning as far as I can tell). This program affords a relatively complete set of tools in a nice unified format, with command line and a graphical front end (easy to automate in other words). It supports full, incremental and differential backups, as well as catalogs, and can write to a file or tape drive, basically a solid, simple, easy to use backup program. BRU is available at http://www.estinc.com/features.html.

Quickstart

Quickstart is more aimed at making an image of the system so that when the hard drive fails/etc. you can quickly re-image a blank disk and have a working system. It can also be used to 'master' a system and then load other systems quickly (as an alternative to say Red Hat's kickstart). It's reasonably priced as well and garnered a good revue in Linux Journal (Nov 1998, page 50). You can get it at: http://www.estinc.com/qsdr.html.

Backup Professional

http://www.unitrends.com/bp.html

CTAR

http://www.unitrends.com/ctar.html

CTAR:NET

http://www.unitrends.com/ctarnet.html

PC ParaChute

http://www.unitrends.com/pcpara.html

Arkeia

Arkeia is a very powerful backup program with a client - server architecture that supports many platforms. This is an 'industrial' strength product and appropriate for heterogeneous environments, it was reviewed in Linux Journal (April 1999, page 38) and you can download a shareware version online and give it a try, the URL is: http://www.arkeia.com/.

Legato Networker

Legato Networker is another enterprise class backup program, with freely available (but unsupported) Linux clients. Legato Networker is available at: http://www.legato.com/Products/html/legato_networker.html and the Linux clients are available from: ftp://ftp.legato.com/pub/Unsupported/Linux_Client/.

Perfect Backup

Perfect Backup supports almost all Linux distributions and has crash recovery. You can get it from: http://www.merlinsoftech.com/nonflash/merlinhome.htm.

Pro's and con's of backup media

There are more things to back data up onto than you can drive a range rover over but here are some of the more popular/sane alternatives:

Name of Media Pro's Con's
Hard Drive It's fast. It's cheap. It's pretty reliable. ($20-$30 USD per gig)  It might not be big enough, and they do fail, usually at the worst possible time. Harder to take offsite as well. RAID is a viable option though. 20 gig drives are $350 USD now.
CDROM  Not susceptible to EMP, and everyone in the developed world has a CDROM drive. Media is also pretty sturdy and cheap ($2 USD per 650 Megs or so) CDROM's do have a finite shelf life of 5-15 years, and not all recordables are equal. Keep away from sunlight, and make sure you have a CDROM drive that will read them.
Tape  It's reliable, you can buy BIG tapes, tape carousels and tape robots, and they're getting cheap enough for almost everyone to own one. Magnetic media, finite life span and some tapes can be easily damaged (you get what you pay for), also make sure the tapes can be read on other tape drives (in case the server burns down....).
Floppies  I'm not kidding, there are rumors some people still use these to backup data. It's a floppy. They go bad and are very small. Great for config files though.
Zip Disks I have yet to damage one, nor have my cats. They hold 100 megs which is good enough for most single user machines. Not everyone has a zip drive, and they are magnetic media. The IDE and SCSI models are passably fast, but the parallel port models are abysmally slow. Watch out for the click of death.
Jazz Drives 1 or 2 gig removable hard drives, my SCSI one averages 5 meg/sec writes. They die. I'm on my third drive. The platters also have a habit of going south if used heavily. And they aren’t cheap.
SyQuest  1.6 gigs, sealed platter, same as above. Sealed cartridges are more reliable. Company did recently declare bankruptcy though. No warranty service.
LS120  120 Megs, and cheap, gaining in popularity. Slow. I'm not kidding. 120 megs over a floppy controller to something that is advertised as "up to 3-4 times faster then a floppy drive".
Printer  Very long shelf life. requires a standard Mark 1 human being as a reading device. Handy for showing consultants and as reference material. Cannot be easily altered. You want to retype a 4000 entry password file? OCR is another option as well.

 
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Written by Kurt Seifried