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The dark side of converged storage networks
Posted by Andrea Mauro on October 10, 2017
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Introduction

The fabric of SAN (means Storage Area Network) with Fibre Channel solutions have always been a dedicated network, with dedicated components (like FC switches).

But, starting with iSCSI and FCoE protocols, the storage fabric could now be shared with the traditional network infrastructure, because at least level 1 and 2 have a common Ethernet layer (for iSCSI also layer 3 and 4 are the same of TCP/IP networks).

Hosts (the initiators) in a converged network use typically Converged Network Adapters (CNAs) that provide both Ethernet and storage functions (usually FCoE and iSCSI). The results are that LAN and SAN are shared on the same physical network:

LAN and SAN shared on the same physical network

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The importance of IeeePriorityTag with converged RDMA Switch Embedded Teaming
Posted by Didier Van Hoye on September 27, 2017
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Introduction

If you read my blog on Switch Embedded Teaming with RDMA (for SMB Direct) you’ll notice that I set the -IeeePriorityTag to “On” on the vNICs that use DCB for QoS. This requires some explanation.

When you configure a Switch Embedded Teaming (SET) vSwitch and define one or more management OS vNICs on which you enable RDMA you will see that the SMB Direct traffic gets it priority tag set correctly. This always happens no matter what you set the -IeeePriorityTag option to. On or Off, it doesn’t make a difference. It works out of the box.

mapped RDMA vNIC to their respective RDMA pNIC

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Why do we always see Responder CQE Errors with RoCE RDMA?
Posted by Didier Van Hoye on June 2, 2017
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Why do we always see Responder CQE Errors with RoCE RDMA?

Anyone who has configured and used SMB Direct with RoCE RDMA Mellanox cards appreciates the excellent diagnostic counters Mellanox provides for use with Windows Performance Monitor. They are instrumental when it comes to finding issues and verifying everything is working correctly.

Many have complained about the complexity of DCB configuration but in all earnest, any large network under congestion which needs specialized configurations has challenges due to scale. This is no different for DCB. You need the will to tackle the job at hand and do it right. Doing anything at scale reliable and consistent means automating it.  Lossless Ethernet, mandatory or not, requires DCB to shine. There is little other choice today until networking technology & newer hardware solutions take an evolutionary step forward. I hope to address this in a future article. But, this I not what we are going to discuss here. We’ve moved beyond that challenge. We’ll talk about one of the issues that confuse a lot of people.

Responder CQE errors report after virtual machines migration from Hyper-V cluster

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