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Snapmirror Performance. (Single stream)

Hello,

I notice a conspicuousness that a Snapmirror connection does not come over 300 MBs. Both systems FAS8200 & Fas8080 are connected with 40 GBits via a LACP. Bottlenecks in the network are excluded and the hard disks are at 10-20% utilization.
Is there an option which controls this?

Snapmirror throttle is unlimited. Currently ONTAP 9.1P7

Many Thanks
Dennis

4 REPLIES 4
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Re: Snapmirror Performance. (Single stream)

Hi there,

 

Can you run this command on all nodes:

 

node run -node * options -option-name replication.throttle

and paste the output?

 

That said - in general it depends on how much other workload is present on both systems, what sort of disks are underneath - and at the end of the day it is a lower priority task.

 

For detailed troubleshooting, you should open a case with our support center - you can do that via the web on https://support.netapp.com

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Re: Snapmirror Performance. (Single stream)

Hi.

 

what do you call a single stream? and what the latency between the two sites?

 

Note that if you using the 40GB card and/or lacp.. you better create multiple intercluster LIFs per node. otherwise the traffic will go via a single 10GB path.

 

Have you tried multiple snapmirror at once. or only single volume? if it's a single volume, there could be a serialization bottleneck, that could be picked up in perfstat and you may get better result on XDP then DP  type (Defualt in 9.3, so worth migrating to anyway).

 

Gidi

Gidi Marcus (Linkedin) - Storage and Microsoft technologies consultant - Hydro IT LTD - UK
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Re: Snapmirror Performance. (Single stream)

 - on a single volume workload (such as snapmirror), you will hit a CPU bottleneck way before the 10G limit so don't focus too much on the network

 - what is the throughput you expect?

 - as already mentioned here, snapmirror operates under low priority compared to user workload. Once a certain CPU threshold is crossed, snapmirror will be throttled. The only way to change that is with a special flag

 - if you'd like to further investigate the issue, we will need a perfstat (as already mentioned) from the source and destination during the entire snapmirror transfer

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Re: Snapmirror Performance. (Single stream)

Hi,

 

Although you have a 40Gb pipe, are they arrays within the same DC or split over two DC's?

Kind regards

 

Andrew Martin 

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