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Half speed on sync
Posted: Tue Nov 11, 2014 9:24 am
by SynthosKralupy
Hello,
I found strange behavior during full sync of two Starwind nodes. I have (simplified) config of starwind cluster, see schema, using latest build v8. When full sync is running I have only one NIC active on receive server. Second "sync" NIC is ready, but performance monitor doesn't shows any traffic.
But this NIC is working normal after sync. I have round robin MPIO policy on vmware ESXi and it works as expected. When I tried manually disable NIC3 for test, all traffic is running on this NIC4 at 1Gbps. And vice versa, when sync has been started in reverse order, from starwind node 2 to 1 - same situation.
Is it normal?

- SW-Sync speed.png (9.87 KiB) Viewed 9797 times
Re: Half speed on sync
Posted: Tue Nov 11, 2014 4:33 pm
by 707kevin
What are the IP addresses for nic1, nic2, nic3 and nic4?
(also, you should really, really consider 10Gb sync channels)
Re: Half speed on sync
Posted: Wed Nov 12, 2014 8:21 am
by SynthosKralupy
Hello 707kevin,
all four NICs are in same subnet:
nic1 - 10.0.2.100
nic2 - 10.0.3.100
nic3 - 10.0.2.101
nic4 - 10.0.3.101
mask 255.255.254.0.
Pavel.
Re: Half speed on sync
Posted: Wed Nov 12, 2014 8:55 pm
by thefinkster
How are the images setup? Thick/Thin (LSFS or no LSFS), level 2 cache or no?
Also, I would make sure each NIC pair is set to unique subnets; per the diagram that StarWind posted. Just change their mask to /24; you'd not even need to VLAN the switch for this test. You can also try to directly connect the systems together bypassing your switch.
And make sure to run iperf tests with advanced commands (-P 4 or 8, for example or -w 32M or 64M etc). Also make sure you do the tcp/ip tuning steps that are listed in a forum sticky; including playing with jumbo frames and doing tests.
If you can't get full NIC speeds over iperf, you won't get them with anything else (for the most part).
Re: Half speed on sync
Posted: Fri Nov 14, 2014 8:43 am
by SynthosKralupy
Hello thefinkster,
thanks for hints, I will try split into separate subnets first. Network speed is not problem itself, it is running almost at 100% kapacity.
BTW, it is thick setup without L2 cache.
Pavel.
Re: Half speed on sync
Posted: Tue Nov 18, 2014 10:07 am
by Anatoly (staff)
thefinkster, thank you for good advises!
SynthosKralupy, please let us know if suggested gave you some results. I`d also recommend you to check if you are running the latest StarWind build.
Re: Half speed on sync
Posted: Wed Nov 19, 2014 3:28 pm
by SynthosKralupy
Great! Network mask has been changed for all NICs, set mask to 24. I created a new LUN so full synchronization has started. I noticed that both pair of NICs started to communicate with each other. Speed is about 1Gbps on all NICs.
Thanks.
Re: Half speed on sync
Posted: Fri Nov 21, 2014 3:53 pm
by Anatoly (staff)
Good to hear that! Thanks for updating us!