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Remote copy slower from secondary to Primary

 
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jruffer
Trusted Contributor

Remote copy slower from secondary to Primary

We had to failover to our DR site because of a power issue at the primary.

We have found that synchronisation is much slower in the reverse direction.

Any ideas what could be causing this?

Jeremy

6 REPLIES
Dennis Handly
Acclaimed Contributor

Re: Remote copy slower from secondary to Primary

Are the two StoreServs the same model and OS version?

Is one more heavily loaded than the other?

jruffer
Trusted Contributor

Re: Remote copy slower from secondary to Primary

Same model and OS.

Normally the target of the remote copy is doing nothing else while the source is our production system.

Dennis Handly
Acclaimed Contributor

Re: Remote copy slower from secondary to Primary

>Normally the target of the remote copy is doing nothing else while the source is our production system.

 

That may explain why it is slower, too busy to write the data?

jruffer
Trusted Contributor

Re: Remote copy slower from secondary to Primary

Found the problem.  It turns out that the default gateway wass missing from one of the replication ports.  Must have gone missing when we had a power outage.

 

It's looking much better now.

jruffer
Trusted Contributor

Re: Remote copy slower from secondary to Primary

The relief was only temporary, it's back to being slow again.

The remote copy we have going from primary to secondary are working fine.

jruffer
Trusted Contributor
Solution

Re: Remote copy slower from secondary to Primary

It looks like we've finally fixed it though we still don't know why it was a problem in one direction and not the other.

The problem is that when heartbeats are missed the 3PAR resets the connections.  The key was to stop the heartbeats from going missing.

We used setcopytarget tput to limit the bandwith to 40% of the link and setrcopytarget tunelinks to the same value with an appropriate latency. In our case 60.  We tried 40 at first and it was a big improvement but we still had dropped heartbeats overnight.