Re: [Bacula-users] Faster reading of Volumes from disk

On Feb 16, 2016, at 3:21 PM, Dan Langille <dan AT langille DOT org> 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.

As a test, I scp'd over all the volumes for one job and timed it:

real 167m15.956s

user 117m51.006s

sys 23m56.653s

FWIW, these copies were done while a ZFS scrub was underway, so if anything, the potential throughput is higher.

The job above, took nearly 11 hours. Something is up.

I tried another test run, just now, but cancelled it after the first two Volumes were read; it was going at about the same rate as the full job mentioned above.

What might account for this vast difference?

Dan Langille - BSDCan / PGCon

dan AT langille DOT org

------------------------------------------------------------------------------
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140

_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users