Hi people
Just out of idle curiosity, am I the only netapp admin who does not know about the super secret flags to allow snapmirror to actually work at reasonable speed?
We were running 8.3.2 cluster mode, and spent weeks looking into why our snapmirrors to our remote site ran so slowly. We were often 2 days behind over 40G networks. Obviously, we focussed on network issues. And we wasted a lot of time. We could make no sense of the problem at all since sometimes it appears to work ok, the later the transfers slowed to a crawl.
We eventually opened a case and it did not take to long for a reply which basically said "why don't you just disable the global snapmirror throttle." I had already looked into such a beast, but found nothing.
As you may or may not know, it turns out to be a per node setting. The name of the flag is repl_throttle_enable. Of course, you can only see such flags or change them on the node, in privileged mode.
Setting the flag to 0 immediately (and I do mean immediately) allowed our snapmirrors to run at the speed you might expect over 40G. Instead of taking 2 days, snapmirror updates now took 2 hours.
We have since upgraded to 9.1. The flags reverted to on, but again can be set to off. I think there is a documented global snapmirror throttle option in 9.1, but I have not looked into that yet.
Are we the only site in the world to have seen this issue? We use snapmirror DR for all our mirrors which may be a factor.
As I said, just idle curiousity and maybe helping someone avoid the time wasting we had.
Regards, pdg
Peter Gray Ph (direct): +61 2 4221 3770 Information Management & Technology Services Ph (switch): +61 2 4221 3555 University of Wollongong Fax: +61 2 4229 1958 Wollongong NSW 2522 Email: pdg@uow.edu.au Australia URL: http://pdg.uow.edu.au