[olug] To RAID or not to RAID

[Lou Duchez]

This is cool, thanks!  I especially like that they talk about how to get 
Windows to do hard links, which I'm probably going to need to do one of 
these days.

> And to follow up with my rsync backup discussion, I found the "rsnapshot"
> which appears to be a fully fleshed out implementation of the multi-state
> backups I mentioned in the previous email.
>
> Here's the URL: http://www.rsnapshot.org/
>
> It's also a pre-made package in my Linux Mint system so and it doesn't
> appear that old.
>
> Dan
>
> On Mon, Sep 22, 2014 at 8:56 PM, Dan Linder <dan at linder.org> wrote:
>
>> This reminded me of an old script I wrote up to keep a number of copies of
>> the data but re-using the files on-disk if the data was the same.
>>
>> Check out this URL: http://www.mikerubel.org/computers/rsync_snapshots/
>>
>> But the gist of it is this (from the page):
>>
>> rm -rf backup.3
>> mv backup.2 backup.3
>> mv backup.1 backup.2
>> cp -al backup.0 backup.1
>> rsync -a --delete source_directory/  backup.0/
>>
>> If the above commands are run once every day, then backup.0, backup.1,
>> backup.2, and backup.3 will appear to each be a full backup of
>> source_directory/ as it appeared today, yesterday, two days ago, and
>> three days ago, respectively--complete, except that permissions and
>> ownerships in old snapshots will get their most recent values (thanks to
>> J.W. Schultz for pointing this out). In reality, the extra storage will be
>> equal to the current size of source_directory/ plus the total size of the
>> changes over the last three days--exactly the same space that a full plus
>> daily incremental backup with dump or tar would have taken.
>>
>> BUT, BEFORE YOU IMPLEMENT THIS, PLEASE READ THE UPDATES ON THE URL LISTED
>> ABOVE.  THERE ARE SOME CLEANER METHODS TO DO THIS that will preserve the
>> ownership and permissions, and optimize disk usage after a number of backup
>> rotations.  (I'm sure someone has a better script that's up-to-date...)
>>
>> I did experiment with using the Win32 version of rsync many years ago, but
>> I don't believe it supported the
>>
>> Dan
>>
>>
>> On Mon, Sep 22, 2014 at 8:32 PM, Obi-Wan <obiwan at jedi.com> wrote:
>>> On 09/22/2014 06:19 PM, Lou Duchez wrote:
>>>> Any chance you've got a friend out there on the Internets who would let
>> you keep a drive at his place?  For my remote backups, I do a two-step
>> process:
>>>> 1)    rsync is a great way to back data up across a network (including
>> the Ethernet), especially where only a little data changes from one backup
>> session to the next.  So let's say I use rsync to back up my data to
>> "/backups/current" on the remote system.  Which I then follow with step 2
>> ...
>>>> 2)    /bin/cp -al /backups/current /backups/[date]
>>>>
>>>> What that does is create a dated backup directory, but thanks to the
>> magic of the "-l" flag, hard links (not symbolic links) to the files in
>> /backups/current are created.  That means I have a logical copy of
>> /backups/current that takes up almost no additional drive space because
>> it's pointing to the same files on the file system.  Now, if any of those
>> files in /backups/current is changed the next time I run rsync, the file in
>> /backups/current is unlinked first and a new file is created -- but the
>> link to the original in /backups/[date] is left completely untouched.
>>>
>>> I don't see anything in the rsync man page that indicates it will break
>> that hard link when updating an existing file.  How does your setup ensure
>> this will happen?  If the link isn't broken, then your old hardlinks will
>> get updated along with your current file when rsync changes it.
>>> --
>>> *Ben "Obi-Wan" Hollingsworth* obiwan at jedi.com <mailto:obiwan at jedi.com>
>> www.Jedi.com <http://www.jedi.com>
>>> The stuff of earth competes for the allegiance I owe only to the
>>> Giver of all good things, so if I stand, let me stand on the
>>> promise that You will pull me through. /-- Rich Mullins/
>>>
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>>
>>
>>
>> --
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>>
>
>