LinuxQuestions.org
Help answer threads with 0 replies.
Go Back   LinuxQuestions.org > Forums > Enterprise Linux Forums > Linux - Enterprise
User Name
Password
Linux - Enterprise This forum is for all items relating to using Linux in the Enterprise.

Notices


Reply
  Search this Thread
Old 12-21-2004, 06:06 PM   #1
abefroman
Senior Member
 
Registered: Feb 2004
Location: lost+found
Distribution: CentOS
Posts: 1,430

Rep: Reputation: 55
How can I instantly mirror data from 1 linux server to another?


How can I instantly mirror data from 1 linux server to another?

I want to have high availability in the event of a hardware failure.
 
Old 12-21-2004, 06:16 PM   #2
sigsegv
Senior Member
 
Registered: Nov 2004
Location: Third rock from the Sun
Distribution: NetBSD-2, FreeBSD-5.4, OpenBSD-3.[67], RHEL[34], OSX 10.4.1
Posts: 1,197

Rep: Reputation: 47
You can't "instantly" mirror data to anything (including a raid mirror), but you can have a cron job that fires rsync to mirror two directories every hour or whatever.
 
Old 12-21-2004, 06:50 PM   #3
sunwj82
LQ Newbie
 
Registered: Dec 2004
Posts: 7

Rep: Reputation: 0
You may find out the answer in


/etc/sysconfig/syslog

/etc/syslog.conf
 
Old 12-21-2004, 07:30 PM   #4
sigsegv
Senior Member
 
Registered: Nov 2004
Location: Third rock from the Sun
Distribution: NetBSD-2, FreeBSD-5.4, OpenBSD-3.[67], RHEL[34], OSX 10.4.1
Posts: 1,197

Rep: Reputation: 47
Quote:
Originally posted by sunwj82
You may find out the answer in


/etc/sysconfig/syslog

/etc/syslog.conf
This is one of those times when I'll readily admit my ignorance ... How will syslog help mirror two servers so that you can have a warm standby in the event of a catastrophic failure?
 
Old 12-21-2004, 07:36 PM   #5
abefroman
Senior Member
 
Registered: Feb 2004
Location: lost+found
Distribution: CentOS
Posts: 1,430

Original Poster
Rep: Reputation: 55
So, corporations use something similar to
* * * * * rsync -r 10.10.0.1:/ 10.10.0.2:/

To ensure high availability and 100% uptime?
 
Old 12-21-2004, 08:18 PM   #6
sigsegv
Senior Member
 
Registered: Nov 2004
Location: Third rock from the Sun
Distribution: NetBSD-2, FreeBSD-5.4, OpenBSD-3.[67], RHEL[34], OSX 10.4.1
Posts: 1,197

Rep: Reputation: 47
Something like that. Ours uses several things like this, but a typical sync line looks like this:

rsync -avWHe ssh / root@server2:/

Be aware though -- to have true 99.999% uptime, you're going to need a load balancer or some other device to handle failover.

And really, it's not very efficient to sync the whole server. You're probably better off to juust sync the stuff that's not part of the base system -- i.e. html files or whatever.

Last edited by sigsegv; 12-21-2004 at 08:21 PM.
 
Old 12-21-2004, 11:21 PM   #7
abefroman
Senior Member
 
Registered: Feb 2004
Location: lost+found
Distribution: CentOS
Posts: 1,430

Original Poster
Rep: Reputation: 55
What is the best way to mirror a whole server? I have a hardware loadbalancer, I just need the data to be mirrored

How are they likely doing it:
http://powweb.com/PowWeb/Technology/Overview
 
Old 12-21-2004, 11:48 PM   #8
sigsegv
Senior Member
 
Registered: Nov 2004
Location: Third rock from the Sun
Distribution: NetBSD-2, FreeBSD-5.4, OpenBSD-3.[67], RHEL[34], OSX 10.4.1
Posts: 1,197

Rep: Reputation: 47
I have no idea how powweb does it. I can tell you how I do it though.

Our site has 10 webservers with mirrored disks. The machines html/images are sync'd at build time, and then the servers are layer 3/4 balanced in front of that.

You can't sync the whole machine or you'll overwrite access logs, messages logs, network interface settings and all the stuff that makes an individual machine individual.
 
Old 12-22-2004, 06:59 AM   #9
Builder
Member
 
Registered: Jun 2004
Location: London
Distribution: Red Hat, SuSE, Gentoo
Posts: 80

Rep: Reputation: 15
Quote:
Originally posted by abefroman
So, corporations use something similar to
* * * * * rsync -r 10.10.0.1:/ 10.10.0.2:/

To ensure high availability and 100% uptime?
No - we used shared storage on an HDS SAN. But I'm guessing you don't have that kind of spare change

If you look at the Red Hat Cluster Suite, you'll see that it requires simultaneous access to the shared storage from all machines in the cluster. This means that SAN is often the only way to go in a production environment as even the external storage units from HP won't allow you to dual initiate with their dual port scsi controller.

I think that the best way to achieve what you seem to be asking for on a budget is rsync. The next best solution might be an HP StorageWorks MSA1000 or the MSA30 MI. But with both of these, while you'll have access to your data from two machines, data lost in a single place is gone from both.

I guess what I'm getting at is are you looking to build an HA solution for availability, are you looking to protect your data from hardware failure, are you looking to protect your data from software failure or are you looking to protect your data from user error - all of these have different solutions
 
Old 12-22-2004, 08:43 PM   #10
abefroman
Senior Member
 
Registered: Feb 2004
Location: lost+found
Distribution: CentOS
Posts: 1,430

Original Poster
Rep: Reputation: 55
Quote:
Originally posted by Builder
are you looking to protect your data from hardware failure, are you looking to protect your data from software failure or are you looking to protect your data from user error - all of these have different solutions
From hardware failure.

Has anyone used unison?
http://www.cis.upenn.edu/~bcpierce/unison
 
Old 01-13-2005, 03:58 AM   #11
anand_kt
Member
 
Registered: Dec 2004
Location: Chennai, India
Distribution: Red Hat, Knoppix
Posts: 86

Rep: Reputation: 15
what server are you trying to failsafe ?
Is it like a webserver, datacenter or ... ?

Cos if its a webserver you can easily do it from your router itself by using round-robin
or some sort of load balancing schema based on ip's

ps : i have not worked with unison. But am guessing its advanced rsync. and not a failsafe.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
DISCUSSION: Using rsync to mirror data between servers david_ross LinuxAnswers Discussion 8 03-29-2012 02:37 AM
Mapping Windows share, then mirror data loadedmind Linux - Networking 5 02-07-2008 04:25 AM
Can I instantly replicate data over 2 drives on different servers with a codafs? abefroman Linux - Hardware 1 09-14-2005 01:03 PM
Rsync to mirror data for backup - having difficulties tapanga Linux - Newbie 1 05-17-2004 06:45 PM
data mirror between machines knobby *BSD 1 07-25-2002 11:58 PM

LinuxQuestions.org > Forums > Enterprise Linux Forums > Linux - Enterprise

All times are GMT -5. The time now is 01:01 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration