Warning, some cursing ahead, I got too wound up when replying to this...

Edward> Without checking the internet, and before you listen to other peoples'
Edward> anecdotes or anything, I'd like to hear your gut feel, I want to know 
what
Edward> your natural instinct is.  What do you think about the reliability of 
the
Edward> following tools?  

Oooh!  A test.  Yummy! 

Edward> If you have personal experience with them, obviously, that
Edward> will shape your perception.  But even with no knowledge or
Edward> experience with a particular tool, I still want to know your
Edward> instinct.  Because your preconceived notions influence
Edward> decisions you make, give you bias in terms of what tools you
Edward> even think about using or researching.

Edward> Focus on reliability.   ;-)

No, you want to focus on restorability of your data in face of
disaster.  It does no good at all to have a reliable backup system if
you can't get the data out.  

Edward> rsync

I don't consider this a backup system because it doesn't keep history
or mutliple versions without a bunch of extra work on top of it.  And
if you do need to 

Edward> rsnapshot

Based on top of rsync, and I do use it (vaguely, I set it up and have
mostly forgotten about it) on a system I help maintain.  But since I
don't move the actual data off site or off system, it's not a good
backup.  

Now it is *easy* to pull back data, assuming you haven't lost the
site/system.  

Edward> rdiff-backup

Same idea as above, but I haven't used it.  The nice thing is that the
data is in a documented accessible format that isn't opaque to you.
In times to need, you can get it back without depending on some
vendor.  

Edward> tar

Great tool in general, but long in the tooth.  Haven't used it for
general backups in a long time because of the limits of spanning
across tape media with it.  For restores, it's a pain to have to scan
through multiple tapes to restore the single file you want to recover
from the middle of tape 5 (or 10, or 20...).  It works, it's simple,
and you can get your data back generally.  But it's not optimal. 

Edward> amanda

I once used amanda years ago and liked it, but this was back when it
couldn't span across tapes, which severely limited it's use on larger
systems.  I also didn't care for the automatic balancing of backup
volumes on a per-night basis.  Since it was based on top of tar at the
time, it was easy to get your data back out in times of need.


Edward> bacula

Ah... my current tool I use at home.  I have a love/hate relationship
with it.   It's well supported, it's continually evolving, I can
manage it from the CLI, etc.  And my data is in a format which I can
parse with some low level tools to get my data back.

But it's also got the worst CLI tool set that you can imagine.  It's
written by a great programmer, with no taste and consistency in his
CLI.  This is where Legato shined in my estimation way back when.  

Bacula works.  It really does.  But when you have to make changes to
the configuration files and add stuff in, you go *insane* trying to
understand how it all hangs together.  It's documented, but poorly.
Someone needs to do a diagram in dotty showing how all the names and
such actually interact so you have a hope of doing things without
spending way too much time on it.  

For example, my tape library died, so I fell back to a standalone
(don't laugh, please!) DLT 7k drive.  Which promptly died a few months
later unable to rewind tapes.  Sigh.  So just this past weekend, I
must have spent four hours or longer getting bacula to use a new 3Tb
disk for backups.  But could I figure out how to make it keep the old
tape based backups as the starting point of my fulls, and just do an
incremental?  No.  I know it's possible, but the docs just don't
support it.


Edward> Any other tools that you'd like to mention, that you're likely to use 
for
Edward> backups

I would go back to Legato Networker in a heartbeat.  It's a
proprietary tool, and not ideal, but damn did it do the job and you
could script the sucker and use it from the CLI over a SSH connection
with *ease*.  Really a great great tool.  This was back in terms of
Network 4.2.6 up through 6.x, which is showing my age.  Once EMC
bought them out, I didn't want to go with them.  

At my current $WORK, we looked at both Legato and Commvault and went
with CommVault.  I regret that decision every day practically.  It's
very flexibile, but it's designed by a committee who is convinced that
Java GUIs are the only way to go, and so they took an older base
(which I never used) and bastardized it.  And they don't test it well
enough for prodcution use.  
 

Now the big issue as I see it is that there's not really useful
definition of the NDMP protocol in regards to what gets written to
tape.  It's mostly just a wrapper around the vendor propritary dump
directly to tape.  Now NDMPv4 does support a third channel which dumps
which file went into which tape chunk (block?  area?  Can't remember
terminology and I won't google til this diatrabe is done.) a file was
written too.  So theoretically, you should be able to load tape M out
of N holding a backup, seek to block X and then just read until you
find file Y to do the restore.  

With Commvault, it's just sucky and slow.  It tells you which tape to
restore, so you pull it back onsite and then fuck me, it asks for yet
another god-damn tape because for some stupid reason it won't bother
to tell you which god damn tape(s) it *might* need.  So the NDMP
support in CommVault, and media support in particular, and index
support of which files are saved on what media, also just sucks big
honking moose c*ck.  I could go on for hours in my rants here. 

Please, for the love of $DEITY, don't let your $WORK or $BOSS buy this
piece of crap software.  They don't test it (ask me about my travails
with Solaris 10 x86_64 media agents and NDMP backups of Netapps which
wasn't working until service back 6 or so of version 9 if you want to
here more cursing....) or make sure it's reliable.  

So ask me again why I think open source software can be better?  At
least you get to keep the pieces when it breaks and you have a hope in
hell of getting your data back without depending on some $VENDOR with
it's collective head up it's ass.  I'm looking at you CommVault.  

Now I must be fair and say that whenver I do need support, it does
eventually get solved and fixed.  But I honestly expect more from my
backup sofware Vendor, they should be reliable.  Scriptable.  Easily
monitoried without a GUI.  And east to generate custom reports
against.

And most importantly, I should be able to know which damn tape(s) I
need to do a restore of a specific set of files on a specific date
without having to pull back every single tape it might need.  


Edward> Follow-up question:  Given that these are all free open source packages,
Edward> which are probably included with your "stable" OS distribution, would 
you
Edward> have bias to assume they're reliable, just because of that?

No, I wouldn't.  But it's a big help because if worse comes to worse,
you can actually figure out what the media format is, and get your
data off there without the need to deal with some $VENDORs useless
support team.   

Also, maybe it's too late to ask this, but what do you mean by
reliable?  That's something which needs to be spelled out more
carefully before you can get a real answer. 

Edward> In a follow-up post, momentarily, I'll explain why I'm asking these
Edward> question.


Thanks for starting this thread, I'm looking forward to reading it
all.  

John
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