sbackup question

[Gene Heskett]

On Thursday 09 October 2014 09:20:36 Jay Ridgley did opine
And Gene did reply:
> Folks,
> 
> I use a network drive as the target for my back ups. My question is, if
> more than one system is backing up to the same drive should each be
> placed in a separate directory on that drive.
> 
> For example:
> 
> Network drive path /big_archive
> system_1	/big_archive/system_1
> system_2	/big_archive/system_2
> 
> In the past I have used just /big_archive and it appeared that if
> backups were done on more than one system per day it got confused and
> would not function properly...
> 
> Thanks,
> Jay

I would do that, but be aware that there may be drives (hopefully rare 
today) out there which can get confused when two sources are writing at 
the same time.  Amanda handles that scenario fairly well in the read phase 
when doing its backups by not asking for two files that are on the same 
"spindle" as that is much easier on the seek mechanics, and doing it 
sequentially is generally faster.  The write mechanism does use a file per 
disk list entry, but writes to a buffer drive, then when that disk list 
entry is completed, writes the resultant file from the buffer drive to the 
final drive, in whatever order they are completed.  Not so important when 
using virtual drives like your NAS, but extremely important when using 
real tapes as there is no such thing as random access to a tape.  That 
also reduces shoe shining when the tape is faster than the feeding 
machine.

Amanda can be pretty fast at everything if the temporary holding disk area 
has its own spindle, aka a second drive, and then uses a third for the 
storage medium.  But I haven't actually set that up here.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS