[ale] Backup software

scott scott at sboss.net
Wed Jun 30 17:07:01 EDT 2010


This is something I could write a (short) book on.  But here goes the 
shorter and more centralized on Brandon's particular server needs.

option 1) hack through the issues with Mondo and use it to create .ISOs 
of system.  You can give it a nas share (like NFS) and mondo will create 
the .ISOs there then you can burn them to DVDs, CDs, etc later.
pros: will have CDs (or DVDs) to boot off of and restore the system to 
that point in time configuration. these can be sent to your DR (disaster 
recovery) site for someone else to use in case Atlanta gets hit by a 
hurricane, tornado, earthquake (we are on a fault line, didnt you 
know?), terrorist attack, etc...
cons: time to set it up.  it is going to do the whole system and you 
dont care about the data.  newer version might let you skip certain 
filesystems (to reduce the time & number of CDs).

option 2) hook up an external usb disk and copy the files that you want 
over to it.  Then if the server goes belly up (and they never do that 
</sarcasm>) you can plug the usb drive into another server and recover 
the files.
pros: cheap to setup and easy to automate.
cons: what happens if the server is struck by lightning or electrical 
surge and takes the server and the external drive out?  what happens 
when the disk is failing? etc.  what happens if the building is leveled 
(or flooded with water)?

option 3) use rsync (over ssh) and an "include these files" file.  Rsync 
can be automated.  the target where you are copying it to can be in the 
same building/data center, across the country, or wherever.  you just 
need network connectivity.  You could do 2 rsyncs every time.  one to a 
local server (same building/data center) and one remote (for when stuff 
goes really bad).  rsync doesnt care.
pros: can be automated.  can do mulitple destinations.  can be near or 
far replciations.  restores are easy to do.
cons: have to maintain the "files to include" list.  although if you 
wanted to, you could automate that too.  rsync is not the fastest tool 
on the planet to do replications. see my note about how rsync works below.


rsync and how it works notes (this is high level not the nuts-n-bolts):
rsync goes through these phases:
* both sides compiles a list of files (and directories since they are 
actually files).
* rsync compares the two lists to determine what needs to be replicated, 
what needs to be deleted, etc.
*(only if using the delete-before option) deletes the "to be deleted" 
files on the target
* copies the files from source to target
* (only if NOT using the delete-before option - this is the default 
option for delete) deletes the "to be deleted" files on the target.

as you get more and more files (quantity of files/directories not sizes 
here), the longer the first two steps take (compiling lists/comparing 
lists).  And sometimes it takes longer to do that then the actual 
copying of data.

to do a restore of the data, you reverse the order of the source and 
target inte rsync line and now you are restoring.

backups:
rsync <whole bunch of option> <source> <target>

restores:
rsync <whole bunch of options> <target> <source>  (using the stuff from 
above).
technically that is not correct.  it is always the <source> then 
<target> but for a restore the <target> is now your <source> and vice versa.

my suggestion to you Brandon for this box (since you dont care about 
data, just the config files) I would do option 3.  Unless you want to 
setup and play with Mondo.  If this is a learning experience so you can 
deploy Mondo onto other systems then that is a different story.  If you 
do option 3, I would automate/cronjob once a week to dump "rpm -qa" to a 
text file that you rsync.  that way you know that a current list of all 
rpms.

I hopefully answered some questions without going on and on and on too 
much. I can do a hour long preso on the various options including the 
differences in DR, HA, CA, and DA... (Disaster Recovery, High 
Availability, Continuous Availability, and Disaster Avoidance respectfully)

let me know if you have other questions..
scott

Brandon Wood wrote:
> This stems from having to reinstall the system after a drive crashed
> (non-raid, no backup of the OS). At this point there are a couple of
> 500gb drives in a RAID 1 setup but I want to make sure I don't have to
> start from scratch should the worst happen.
>
> I'm running CentOS 5.5 on a Proliant ML350 G6. The two 500gb drives are
> setup with software raid in linux currently while the large data drives
> are using the SmartArray raid hardware. I only mention this as mondo had
> some complaints about the raid setup.
>
> I doubt the OS will be messed with much more beyond this point and the
> scripts that do the data processing are backed up on their own. The data
> produced is sent off to another server so there isn't much that changes
> as time goes on so the snapshot may cover me. But I am interested in
> hearing your suggestions for backups / disaster recovery.
>
>
> On Wed, Jun 30, 2010 at 6:47 PM, scott <scott at sboss.net
> <mailto:scott at sboss.net>> wrote:
>
>     are you looking for "backups"? "disaster recovery"? or "system image"?
>
>     mondo works well for recovering a system from a point in time snapshot
>     of the system (when you did the mondo image create - cant remember the
>     terminology right now).
>
>     mondo is not a backup and recovery tool.
>
>     mondo is not for disaster recovery (unless you just want to recovery
>     from that one time point in time snapshot).
>
>     it has been a little while since I used mondo but it has worked well for
>     me in the past.  target HD doesnt have to be the same size.  It can be
>     larger or just larger than what you have backed up.
>
>     for instance:
>     current HD = 1Tb drive. But only using 300gig
>
>     recovery system doesnt have to have a 1TB drive.  a 320gig drive from
>     newegg would be fine.  If you are recovering to a non-same-sized drive,
>     you have to go into the system at recovery time (the one you boot off
>     of) and change the drive specs before the actual recovery.
>
>     scott
>
>
>     Brandon Wood wrote:
>      > All,
>      >    I am looking to create an image of a live system and want to know
>      > what software is suggested for this purpose. I've done some searching
>      > and came across 'mondo' and am trying it out now.
>      >
>      > Does anyone have any better suggestions or success stories they
>     want to
>      > share?
>      >
>      > -Woody
>      >
>      >
>      >
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