[clue-tech] Custom partition scheme?

[Mike Bean]

Seconded.  In two years at this job, I've seen allot of snapshot related, we
call them "resume generating events".

Bean

On Wed, Sep 22, 2010 at 5:58 PM, Nate Duehr <nate at natetech.com> wrote:

>
> > In my environment, mostly virtualized servers in VMware Server on Linux,
> LVM snapshots make simple backups possible. Without LVM snapshots, backups
> would be a nightmare.
> >
>
> An LVM snapshot isn't a copy of the data... it just marks where the
> snapshot took place, and then knows how to "get back there"... a Hansel
> and Gretel trail of breadcrumbs so to speak.  (It keeps track of the
> original inode numbers.)
>
> I have used snapshots on LVM and other filesystem types that are capable
> of snapshots to "freeze" the filesystem so a relatively slower
> backup-to-tape system could then back that snapshot up over a weekend's
> time, so that no changes are taking place to the data, while the backup
> is running.  That works well.
>
> But if LVM itself fails, the snapshots aren't copies, and they're gone
> gone gone... they're not a substitute for getting the data off, and onto
> another platter, tape, CD, whatever...
>
> As a tool to "freeze" everything so a backup can be taken, tools like
> LVM are great.  (Don't forget to "quiet" your databases and other things
> on that disk, if you have things there that aren't just files, but are
> actively being written to like binary DB spaces, etc.)
>
> My point was only that the limitations of the tool must be known, and
> one of those is that LVM *can* fail, just like anything else...
>
> It doesn't happen often, but I've seen it (once)... it took out the
> machine.  I've also seen professional grade but similar tools like
> Veritas barf and take out all of someone's data too... there's all sorts
> of ugly once-in-a-lifetime failures that the only thing that will fix
> them is good backups, and a bare-metal recovery plan!
>
> So if you meant that LVM is a useful tool if you plan to use it as a way
> to "quiet" your filesystem you're backing up to somewhere else, I
> definitely agree, and building with LVM in mind up-front is required.
>  But having LVM on by default for folks without a real plan on how to
> manage their systems, is kinda silly on the part of many Linux distros,
> and just adds complexity they may not (or may...) need.
>
> I don't ascribe to the "turn it all on, we might need it" philosophy of
> system management, because every 100 lines of code has at least one bug
> in it... the less overall code running, the less overall risk of
> failures... in my humble opinion.  There's enough complexity in the
> computing world without turning on things like LVM by default long
> before a new sysadmin even knows what it is, and what they can (and
> can't) use it for.  :-)
>
> Nate
> _______________________________________________
> clue-tech mailing list
> clue-tech at cluedenver.org
> http://cluedenver.org/mailman/listinfo/clue-tech
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://cluedenver.org/pipermail/clue-tech/attachments/20100922/8637fa16/attachment.html