Pillar Axiom: iSCSI best practices

Asset ID:	1-79-1497895.1
Update Date:	2016-06-01
Keywords:

Solution Type Predictive Self-Healing Sure

Solution 1497895.1 : Pillar Axiom: iSCSI best practices

Applies to:

Pillar Axiom 500 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Pillar Axiom 600 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Information in this document applies to any platform.

Purpose

This paper provides the guidelines for iSCSI Network best practices not covered in iSCSI Integration Guides or Administration Guide.

To discuss this information further with Oracle experts and industry peers, we encourage you to review, join or start a discussion in the My Oracle Support Community - Disk Storage Pillar Axiom System

Details

Topology Best practices

The logical topology above will aid in creating an optimized and highly available configuration. The blue and maroon paths show the logical connections between the initiator and targets. This topology is best employed when the Sever OS supports AxiomONE Path Management software or has built in ALUA support such as VMWare where preferred paths can be configured and persisted. If the Server OS does not have a supporting AxiomONE Path Manager solution or tested ALUA support and it currently on the Pillar Data Systems support matrix the server should be attached in a single path configuration.
Please refer to Pillar Axiom OS specific iSCSI best practices documentation and Administrator Guide when ever possible.

2. ISCSI BEST PRACTICES

2.1 AXIOM ISCSI BEST PRACTICES

The basic configuration requires assignment of an IP for 2 or 4 of the Slammer iSCSI ports.

For R3 or R4 Axioms
Log in to the Pillar Axiom® GUI, click on Storage->Slammer Ports and using the pull down menu on the bottom select “Modify iSCSI Port Settings” and enter the IP information for each iSCSI Slammer port. The result should list an IP for each port.

For R5 Axioms
Log in to the Pillar Axiom GUI, click on the Configure Tab -> Storage->Slammer Ports and on the right pane, select the Slammer, right click and select “Modify iSCSI Port Settings” and enter the IP information for each iSCSI Slammer port. The result should list an IP for each port.

Note: Hosts with APM installed should expose all 4 Slammer ports and utilize round robin access to the preferred paths.

IMPORTANT:
The Axiom’s iSCSI HBAs can handle 512 outstanding IO requests per port at any one time. For HA considerations iSCSI initiators should not exceed 256 outstanding IO’s per port so in failover situation there is available bandwidth to service traffic from the failed over port.
If HA is not a concern then limit aggregated execution throttle to a maximum of 512 for host connected to any single port.
For example: If you have 4 hosts with 2 iSCSI HBA each configured to access Slammer1 CU0 Port0 /Port 1 in round robin. Your execution throttle for the host should be set to 256/8=32 on each host. You may fine tune this if you find through trending as necessary.
Follow the HBA vendor or iSCSI software initiator configuration to set execution throttle or queue depth to appropriate settings.
Check with Oracle Customer Support or your account representative quarterly for the latest recommended AxiomONE software and AxiomOne Path manager.

2.2 NETWORKING BEST PRACTICES

Use non blocking switches and auto negotiate speed on the switches for the Axiom iSCSI ports.
DHCP can be used if the leases are perpetual but it is highly recommended to use static IP addresses.
Disable unicast storm control on iSCSI ports on the switchs. Most switches have unicast storm control disabled by default. If your switch has this enabled, you should disable this on the ports connected to iSCSI hosts and targets to avoid packet loss.
Enable Flow Control on network switches and adapters; flow control ensures a receiver can make the sender pace its speed and is important in avoiding data loss.
Ensure spanning tree algorithm for detecting loops is turned off; loop detection introduces a delay in making a port become usable for data transfer and may lead to application timeouts
Segregate SAN and LAN traffic. iSCSI SAN interfaces should be separated from other corporate network traffic (LAN). Servers should use dedicated NICs for SAN traffic when not using dedicated HBAs. Deploying iSCSI disks on a separate network helps to minimize network congestion and latency. Additionally, iSCSI data is more secure when flowing via dedicated iSCSI networks
Segregate SAN & LAN traffic using port based VLANs or physically separate networks. The Axiom cannot currently configure specified VLAN tags for its interface and relies on the switch to segregate VLAN traffic.
For each Server, configure multiple paths with additional NICs or iSCSI HBAs for high availability and use AxiomOne Path Manager (where supported) to create additional connections to the Axiom iSCSI storage ports through redundant Ethernet switch fabrics.
For Microsoft SAN Hosts without HBAs, unbind File and Print Sharing from the iSCSI NIC.
Use Gigabit Ethernet connections for high speed access to storage. Congested or lower speed networks can cause latency issues that disrupt access to iSCSI storage and applications running on iSCSI devices. iSCSI is suitable for WAN and lower speed implementations including replication where latency and bandwidth are not a concern.
Use Server class NICs when HBAs are not an option. It is recommended to use NICs which are designed for enterprise networking and storage applications.
Use CAT6 rated cables for Gigabit Network Infrastructures.
Use Jumbo Frames (MTU 9000) if supported in your network infrastructure. Jumbo Frames can be used to allow more data to be transferred with each Ethernet transaction and reduce the number of frames. This larger frame size reduces the overhead on both your servers and iSCSI targets. For end to end support, each device in the network needs to support Jumbo frames including the NIC / HBA and Ethernet switches.
Ensure physical security
Use CHAP authentication because that ensures each host has its own password.
Use iSNS for discovery

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