scp can move binary copies of blocks very efficiently.  A copy (or 
migrate) job reads one record (generally smaller than blocks) one at a 
time, and repacks them into a new block.  The block is then checksummed 
(takes significant time) before it is written.  Look at your CPU usage 
that should largely explain the speed difference.


Best regards,
Kern

On 02/17/2016 06:21 AM, Dan Langille wrote:
> I can scp a 5GB Volume from one system to another in about 90 seconds.
>
> Why does that take the SD 8-10 minutes to do the same?
>
> The two systems are on the same 1Gb/s network.  We are copying from HDD
> local to SSD remote.
>
> I'm running a copy job, from disk on one SD to tape on another SD.  Data
> spooling is enabled.
>
> The full job can be seen here
> https://gist.github.com/dlangille/210fd8a8c3418f9004f6 :
>
> 15-Feb 13:32 crey-sd JobId 231187: Forward spacing Volume
> "FullAuto-3531" to file:block 0:216.
> 15-Feb 13:41 crey-sd JobId 231187: End of Volume at file 1 on device
> "vDrive-0" (/usr/local/bacula/volumes), Volume "FullAuto-3531"
> 15-Feb 13:41 crey-sd JobId 231187: Ready to read from volume
> "FullAuto-3534" on file device "vDrive-0" (/usr/local/bacula/volumes).
> 15-Feb 13:41 crey-sd JobId 231187: Forward spacing Volume
> "FullAuto-3534" to file:block 0:216.
> 15-Feb 13:51 crey-sd JobId 231187: End of Volume at file 1 on device
> "vDrive-0" (/usr/local/bacula/volumes), Volume "FullAuto-3534"
> 15-Feb 13:51 crey-sd JobId 231187: Ready to read from volume
> "FullAuto-3582" on file device "vDrive-0" (/usr/local/bacula/volumes).
> 15-Feb 13:51 crey-sd JobId 231187: Forward spacing Volume
> "FullAuto-3582" to file:block 0:216.
> 15-Feb 13:59 crey-sd JobId 231187: End of Volume at file 1 on device
> "vDrive-0" (/usr/local/bacula/volumes), Volume "FullAuto-3582"
> 15-Feb 13:59 crey-sd JobId 231187: Ready to read from volume
> "FullAuto-3594" on file device "vDrive-0" (/usr/local/bacula/volumes).
> 15-Feb 13:59 crey-sd JobId 231187: Forward spacing Volume
> "FullAuto-3594" to file:block 0:218.
>
> Each volume is 5G and it's taking the SD nearly three times longer than
> scp to transfer.
>
> $ ls -l FullAuto-3531 FullAuto-3534 FullAuto-3582  FullAuto-3594
> -rw-r-----  1 bacula  bacula  5368688762 Feb  7 03:26 FullAuto-3531
> -rw-r-----  1 bacula  bacula  5368688716 Feb  7 03:29 FullAuto-3534
> -rw-r-----  1 bacula  bacula  5368688096 Feb  7 04:29 FullAuto-3582
> -rw-r-----  1 bacula  bacula  5368688834 Feb  7 04:31 FullAuto-3594
>
> This is the device in use:
>
> Device {
>    Name           = vDrive-0
>    Media Type     = File
>    Archive Device = /usr/local/bacula/volumes
>    LabelMedia     = yes
>    Random Access  = yes
>    AutomaticMount = yes
>    RemovableMedia = no
>    AlwaysOpen     = no
>
>    Autochanger    = yes
>    Drive Index    = 0
>
>    Maximum Concurrent Jobs = 1
>    Volume Poll Interval    = 15
> }
>
> --
> Dan Langille - BSDCan / PGCon
> dan AT langille DOT org <mailto:dan AT langille DOT org>
>
>
>
>
>
>
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