Hi Jeff,

AFAIK as previously mentioned, only network speed is affected.

But did you think of the priority command?
There you can change relative (!) priorities, e.g. system (-> SnapMirror) vs. user.

priority set volume prodvol level=high system=low
Set the priority scheduling policy for volume  prodvol  to  high compared to other volumes. Also prioritize system operations for the volume low  compared to user operations on the same volume. These options are enabled by this operation if priority on has been previous issued.

So you would set 'level=high' on the volumes where the users are impacted and 'system=low' and maybe "level=low" (if the source isn't the one where the users are impacted) to the volumes involved in the SnapMirror.

Don't forget to set 'priority on'.
And maybe 'priority off' after the snapmirror is through if you want to go back to the previous behavior.


HTH                                 (Hi Oldtimers, still know this one? - Hope That Helps...)

Sebastian



On 01.08.2013 07:15, Jeff Cleverley wrote:
I did try different positions for the -k.  It didn't seem to matter. 

Jeff

On Wed, Jul 31, 2013 at 8:45 PM, steve klise <sklise@hotmail.com> wrote:
I am not sure, but you may want to change your syntax to put the -k before the -S; Not sure if that really matters, but this is what I found in one of the docs..
 
Good luck. 
 

snapmirror update [-k n] -S source_system:source_volume


[dest_system:]dest_volume

 
Date: Wed, 31 Jul 2013 19:54:46 -0600
Subject: Snapmirror throttle not working
From: jeff.cleverley@avagotech.com
To: Toasters@teaparty.net

Greetings,

I'm running 8.1.2P4, 7-mode on some 6290s.а I need to do some snapmirrors to re-balance some disk space.а The -k option to throttle the transfer doesn't seem to be having any effect.а I've tried modifying the placement of the -k but it doesn't seem to matter.а I also tried to modify it after it was running and it doesn't seem to help either.а Here is the command I'm running:


snapmirror initialize -S sm15_3 -k 10000 new_sm15_3

If I'm understanding correctly, this should be allowing 10MB/s.

The source and destination are on the same file system.а Here is a cut of a sysstat 3 after starting it:

аCPUаааа NFSааа CIFSааа HTTPаааа Netаа kB/sааа Diskаа kB/sааа Tapeаа kB/sа Cache
ааааааааааааааааааааааааааааааааа inааа outааа readа writeааа readа writeааа age

73%аааа 598аааааа 0аааааа 0ааа 2091 349080а 338016ааа 271аааааа 0ааааа 0аааа 7
а71%ааа 1019аааааа 0аааааа 0ааа 2046 319892а 324019а 13114аааааа 0ааааа 0аааа 0s
а71%ааа 2800аааааа 0аааааа 0ааа 3880 330527а 343528а 17379аааааа 0ааааа 0аааа 7
а69%ааа 1440аааааа 0аааааа 0ааа 3405 330279а 392647а 22343аааааа 0ааааа 0аааа 0s
а87%ааа 1614аааааа 0аааааа 0ааа 2128 320151а 607753 168553аааааа 0ааааа 0аааа 0s
а87%аааа 827аааааа 0аааааа 0ааа 5652 244701а 584436 371689аааааа 0ааааа 0аааа 0s
а91%аааа 897аааааа 0аааааа 0ааа 4242 344072а 680454 386373аааааа 0ааааа 0аааа 0s

As you can see, the disk read/write counts go way up.а This is causing some noticeable latency in the nfs access for clients.а While I really like the new hardware can pump data around, I need to be able to control it.

What am I doing wrong?

Thanks,

Jeff

--
Jeff Cleverley
Unix Systems Administrator
4380 Ziegler Road
Fort Collins, Colorado 80525
970-288-4611

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--
Jeff Cleverley
Unix Systems Administrator
4380 Ziegler Road
Fort Collins, Colorado 80525
970-288-4611


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