Re: Mirroring a Server

[Alvin Oga <aoga@Mail.Linux-Consulting.com>]

hi ricardo

> 	Any one can suggest me softwares for mirror a server (Backup) ?

lots of backup and mirroring software..
	- backup and mirroring is very very different...

assuming you want mirroring...
	mirror.pl	- common software...
	=========

if you want to copy/mirror hda(sda)  to hdb(sdb)  --> use raid1
	( hardware or software raid )

if you want something old/simple...to mirror from cron...
    in quickie psuedo code:
	#!/usr/bin/perl
	#
	# run this perioidicaly fron cron
	#
	$DIR = "/etc /root /opt /home /usr/local /var/log " ;	# directories you want to mirror
	#
	$INC = "-mtime -1";	# once a day
	#INC = "-mmin -60";	# every hour
	#
	` mount /Mirror `;	( where /Mirror is a local disk or disk on another machine )
	` find $DIR $INC -print | tar zcf - -T - | ( cd /Mirror ; tar zxvfp - ) `;
	` umount /Mirror `;	# don't leave your mirror mounted....rm -rf /....
	# 
	# quick and simple....and full of holes...

- and yeah...the above grew into a "part-time job" to tke care of everybody's "issues"
	- was fun... lots of issues...
	
if you cannot loss of any data...
	- the program creating the data should save the data in both places...

if you cannot handle the downtime due to hardware/software failure during the
"mirroring" you need to do mirroring at the disk controller level...
	- problem with it...is if your original data is corrupted...your mirror will
	be also instantly corrupted...

what if the "mirror" disk gets 100% full...
what if the mirror fails to run or complete...than the new pass does not pickup the last pass + this pass
	- hardware down, network down, 2Gb files... "window's style names" etc..etc..etc...
add a html gui to search the backup/mirror logs and see that certain key files is mirrored....

-
- sorry...i had fun doing the "what ifs" across 192Gb of data...
-

c ya
alvin