Amanda-Users

RE: Amanda 2.6.0 spanning

2008-06-23 10:49:49
Subject: RE: Amanda 2.6.0 spanning
From: "Johan Booysen" <johan AT matrix-data.co DOT uk>
To: "Paul Bijnens" <Paul.Bijnens AT xplanation DOT com>, "Amanda List" <amanda-users AT amanda DOT org>
Date: Mon, 23 Jun 2008 15:38:04 +0100
Thanks very much!  I'll definitely give this a go.

Johan

-----Original Message-----
From: Paul Bijnens [mailto:Paul.Bijnens AT xplanation DOT com] 
Sent: 23 June 2008 15:34
To: Johan Booysen; Amanda List
Subject: Re: Amanda 2.6.0 spanning

On 2008-06-23 15:49, Johan Booysen wrote:
> That's very interesting.  Not sure I completely understand your setup
-
> one "normal" config from Monday to Thursday, and another config doing
a
> level 0 only on Fridays?

Yes, I have two configs for amanda.
On Tuesday to Saterday at 0:04 early morning, I run the "daily" config.
That config uses vtapes on disk as backup using the chg-disk changer.
This is a classical run having fulls and incrementals mixed each day.
It includes all the disks except some large volumes (that contain
very static files only).
Using vtapes means there is no hassle to juggle tapes each day, and
restores are easy and fast as well.

On sunday morning, I run the "archive" config.  This config does only
full dumps using LTO2 tapes.  Those tapes are stored offsite.
I have 2 LTO2 tape drives, joined together with chg-multi to emulate
a changer with 2 tapes.
The config has more to dump than those 2 tapes, so I instruct amanda
to collect the rest to holdingdisk using the parameters "maxdumpsize"
and "reserve".
Here are specialised settings in "archive/amanda.conf":

   dumpcycle 0          # results in mostly full dumps, if enough
capacity
                        # to store them on tape and holdingdisk
   runspersycle 1
   tapecycle 5 tapes    # I have many more, but allow overwriting fast
   runtapes 2
   tpchanger "chg-multi"
   changerfile "chg-multi.conf"
   tapetype LTO2
   amrecover_do_fsf on
   amrecover_check_label on
   amrecover_changer "changer"
   taperalgo "largestfit"       # make better use of the tape capacity
   reserve 0            # Important; default= 100% reserved for
incrementals
   maxdumpsize 800g     # Important; default= runtapes times
tapecapacity
   define dumptype global {     # included by every dumptype
      program "GNUTAR"
      index yes
      record no         # Important; do not confuse the "daily" config!
      compress client fast
      skip-incr yes     # never do incrementals, even when out of space
      strategy noinc    # avoid calculating estimates for incrementals
   }

For some slower DLE's, I even have "estimate calcize" and even
"estimate server" to avoid wasting time doing the estimates.

The file "chg-multi.conf", in the same directory as amanda.conf
contains:

    multieject 0
    firstslot 1
    lastslot 2
    gravity
    needeject 0
    ejectdelay 0
    statefile /var/amanda/archive/changer-status
    slot 1 /dev/nst0
    slot 2 /dev/nst1



> 
> Anyway, I happen to have 2 identical tape drives, and the idea of
using
> both to "emulate a changer with 2 tapes" (like you do) sounds like a
> good plan.
> 
> How did you set that up in amanda.conf (I'd imagine that I would have
> /dev/nst0 and /dev/nst1 when both are installed)?
> 
> E.g.
> runtapes (??)
> tpchanger "chg-multi" 
> tapedev "tape:/dev/nst0" (Specify 2 tape drives?)
> changerfile "/etc/amanda/daily/changer.conf" (Need any parameters set
in
> this file?)
> changerdev "/dev/null" (??)

See above (chg-multi ignores the changerdev parameter - you may omit it)


> 
> How do you handle restores?  If one tape drive dies, and you have to
> restore but Amanda thinks there should be 2 slots, how would you
handle
> that?

As you noticed I used the parameter "amrecover_changer" to give my
changer a name. Then I can do:
    amrecover -d changer
        (Actually, I made that the default builtin device)
And then amanda knows how to handle the two slots in my changer
all by itself.
When one tape drives dies, you can do two things.
Explicitly mention the device you want to use for recovery:
   amrecover -d /dev/nst1
or (temporarily) change the settings in chg-multi-conf
to:
   ...
   firstslot 1
   lastslot 1   # until the drive comes back from repair
   ...
   # slot 1 /dev/nst0
   # slot 2 /dev/nst1
   slot 1 /dev/nst1 #  drive nst0 is broken


> 
> Thank you.
> 
> Johan
> 
> -----Original Message-----
> From: Paul Bijnens [mailto:Paul.Bijnens AT xplanation DOT com] 
> Sent: 23 June 2008 13:21
> To: Johan Booysen
> Subject: Re: Amanda 2.6.0 spanning
> 
> On 2008-06-23 13:43, Johan Booysen wrote:
>> Is there anyone who is actually using chg-manual for their Amanda
> setup,
>> who would be willing to give me an example of their config files,
such
>> as amanda.conf and changer.conf (changerfile parameter)?
> 
> Can't help with chg-manual, but...
> 
> I avoid the use of chg-manual by having a large holdingdisk (4 disks
> 500GB each in raid5).
> I set "maxdumpsize" to a value large enough to dump what is needed
> in the run (800 Gbyte currently).
> 
> For my archive run (full dumps only on weekends), I have two LTO2
> tapedrives (using chg-multi to emulate a changer with 2 tapes), but
> the total backup volume now spans 5 tapes.
> 
> The first two tapes are written during the normal dump during
> the weekend.
> On monday morning I insert the next two tapes, and run amflush.
> Somewhere early afternoon, I get a mail from amanda saying still
> some files are left on holdingdisk, so I insert the next tape
> and run amflush once again for last bits.
> 
> Works good enough for me.
> And does not need manual intervention DURING a backup, like chg-manual
> does.
> I prefer having 2 tapedrives, instead of one (usually expensive)
> changer.  That way i'm not completely blocked when a tapedrive needs
> repair.
> 



-- 

Paul Bijnens, xplanation Technology Services        Tel  +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM    Fax  +32 16 397.512
http://www.xplanation.com/          email:  Paul.Bijnens AT xplanation DOT com
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