This best practice document was created to share my production experience in architecting, implementing, and managing many ONTAP 7-Mode HA pairs and over 30 ONTAP SAN clusters. This knowledge is based on real-world experiences of iSCSI deployments that I’ve encountered over the years. This document was used as reference material during the iSCSI Best Practices whiteboard session at NetApp Insight 2018 in Las Vegas. If you are looking for some tested best practices to help you be successful with your iSCSI deployments, then keep reading.
Before getting into it, I wanted to establish a few key definitions as well as a quick overview of NetApp Unified Storage.
NAS – Network Attached Storage: File-based storage (NFS and SMB (CIFS), SMB3) in which ONTAP controls the file system.
SAN – Storage Area Network: Block-based storage (FC, FCoE, iSCSI) in which the host controls the file system.
LUN – Logical Unit Number: A logical representation of an attached SCSI disk.
SCSI – Small Computer Systems Interface: A set of standards that define commands, protocols, and interfaces that are used to transmit data. SCSI allows low-level access to data in units of 512-byte blocks. This is highly efficient and has low overhead compared to NAS (file-level) access. SCSI has a high level of resiliency that makes it perfect for an enterprise-level protocol. SAN uses SCSI-3 protocol.
FC SAN – Fiber Channel SAN: Uses FC protocol to communicate over FC ports. FC encapsulates SCSI commands in FC frames. IP SAN – iSCSI SAN: Uses iSCSI protocol to communicate over Ethernet ports. iSCSI encapsulates SCSI commands in IP packets. Uses TCP port 3260. In a FC SAN, a worldwide node name (WWNN) describes a machine, and a worldwide port name (WWPN) describes a physical port that is attached to that machine. In an IP SAN, the node name describes a machine, and the portal describes a physical port. Each iSCSI node must have a node name. There are two supported node name formats: IQN (iSCSI Qualified Name) and EUI (Extended Unique Identifier).
Lee is a Senior Storage Engineer, Storage Architect, and NetApp Subject Matter Expert, as well as a member of NetApp United. He has 25 years of technical experience in the IT industry with an emphasis on supporting engineering resources. He is a hardcore gearhead, and is very passionate about automobile and motorcycle racing. He’s also an avid photographer and a FCC Licensed Amateur Radio Operator and Emergency Communications Volunteer for the County of Santa Clara and City of Morgan Hill, CA.