Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays Dell EMC Engineering December 2016 A Dell Best Practices Guide
Revisions Date Description March 2011 Initial publication April 2012 Correction in Figure 10 December 2016 Updated to include new branding and formatting Acknowledgements This paper was produced by the following members of the Dell Storage team: Engineering: Chuck Armstrong The information in this publication is provided “as is.” Dell Inc.
Table of contents Revisions.............................................................................................................................................................................2 Acknowledgements .............................................................................................................................................................2 1 Introduction ......................................................................................................................
1 Introduction This paper presents network design recommendations and best practices for integration of 10Gb Dell™ Storage PS Series arrays into an existing 1Gb PS Series iSCSI SAN environment. By combining PS Series 10Gb storage arrays with industry standard Ethernet switches and the 10Gb Ethernet NIC options available with Dell EMC™ PowerEdge™ servers, our customers have the ability to build end-to-end 10Gb high-performance iSCSI Storage Area Network (SAN) infrastructures.
2 Integration strategies Before we begin describing integration strategies in detail, we first want to define the fully redundant iSCSI SAN designs used as building blocks for integration and testing. Figure 1 shows a 1Gb redundant iSCSI SAN design using a pair of stacked Dell Networking N or S Series 1Gb switches connecting to one or more PS Series 1Gb storage arrays.
2.1 Design considerations for a mixed speed PS Series SAN To design mixed speed PS Series SANs, two key integration questions require focus: First: How do you properly design a mixed speed switched Ethernet network fabric? Proper design and configuration of the Ethernet switching fabric for 1Gb SANs is critical to achieving and maintaining performance and reliability requirements. The same is true for 10Gb SANs.
Mixed speed PS Series SAN Referring to Figure 3, there are some important design considerations to be aware of: Each of the 1Gb switches is configured with one dual-port 10Gb uplink module and one stacking module. The stacking module is used to create a single logical switching fabric out of the two 1Gb switches. The 10Gb uplink modules are used for creating a single 40Gb LAG (all four ports from the stack) uplinks to the 10Gb stacked switches.
3 Switch integration configuration Connecting the 1Gb and 10Gb switch fabrics for iSCSI storage traffic can be accomplished using one of three methods, depending on the capabilities of the switches being used. Note: Stacking is a method by which multiple switches are connected using a proprietary stacking port and thereafter are managed as, and behave as a single switch.
connections can result in loss of access to storage in the event of a switch failure. Figure 5 shows an example of split connect. Additionally, Rapid Spanning Tree (RSTP) would need to be configured appropriately to block the loop path for traffic. Note: Configuration documentation for specific supported switches can be found at the Rapid EqualLogic Configuration Portal. Stacked 1Gb fabric LAGd to a LAG-connected 10Gb fabric – use of RSTP is required 3.
LAG connections for all 1Gb and 10Gb switches – straight-through LAG for each connection 10 Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays | BP1008
4 Pool architecture and volume placement testing When integrating 10Gb arrays into existing 1Gb PS Series SANs you must also consider how you locate volumes within the available pools.
B: One PowerEdge server with two 1Gb SAN ports connecting to four volumes in one PS Series 10Gb array via stacked Dell Networking N3000 Series switches and LAGd Dell Networking N4000 Series switches C: One PowerEdge server with two 1Gb SAN ports connecting simultaneously to separate speed pools: two volumes in one PS Series 1Gb array and two volumes in one PS Series 10Gb array.
1Gb host performance 110.00% 105.00% 100.00% 95.00% 90.00% 85.00% 80.00% 75.00% 70.00% IOPS MB/s Latency (ms) IOPS Seq. write MB/s Latency (ms) IOPS Seq. read 1Gb storage MB/s Latency (ms) Random R/W 10Gb storage Comparison of 1Gb initiator connecting to 1Gb and 10Gb storage targets The information shown in Figure 8 identifies some differences in sequential I/O performance.
1Gb host pool performance comparison: Mixed speed targets in separate pools versus targets in a single mixed speed pool 1Gb host: Pool performance 105.00% 100.00% 95.00% 90.00% 85.00% 80.00% IOPS MB/s Seq. write Latency (ms) IOPS MB/s Latency (ms) IOPS Seq.
4.2 Comparing pool design and volume placement: 10Gb host initiator The same test sequences from the previous section were repeated using a 10Gb initiator on the host: E. One PowerEdge server with two 10Gb SAN ports connecting to four volumes in one PS Series 10Gb array using LAGd Dell Networking N4000 Series switches. F.
10Gb host performance 250.00% 200.00% 150.00% 100.00% 50.00% 0.00% IOPS MB/s Latency (ms) IOPS Seq. write MB/s Latency (ms) IOPS Seq. read 1Gb storage MB/s Latency (ms) Random R/W 10Gb storage Comparison of 10Gb host initiator connecting to 1Gb and 10Gb storage targets The information shown in Figure 12 indicates sequential read performance significantly increases with 10Gb storage targets as compared to 1Gb storage targets.
10Gb host pool performance comparison: Mixed speed targets in separate pools versus targets in a single mixed speed pool 10Gb host: Pool performance 160.00% 140.00% 120.00% 100.00% 80.00% 60.00% 40.00% 20.00% 0.00% IOPS MB/s Seq. write Latency (ms) IOPS MB/s Latency (ms) IOPS Seq.
4.3 Analysis of pool design and architecture test results For 1Gb host initiators, it is apparent that the placement of volumes in either separate, single speed pools or a single mixed speed pool results in very little performance change. However, 1Gb host initiators that will be migrated to 10Gb host initiators in the future need to be considered. For hosts that will be migrated, the recommendations for 10Gb initiators should be followed.
5 Best practice recommendations The results presented in this paper indicate that attention must be paid to some important SAN design considerations when integrating of 10Gb PS Series arrays into an existing 1Gb PS Series SAN. 19 When integrating 10Gb switches into your existing 1Gb environment, utilize stacking on both sets of switches if possible, and connect the stacked switches using split uplink LAG to create a highly available switch fabric.
A 1Gb and 10Gb host SAN tests: full test results A.1 1Gb host SAN test results The baseline 1Gb I/O performance data in Figure 15 corresponds to two 1Gb host ports accessing four 100GB volumes on a single 1Gb array. During the baseline test, all traffic was isolated to the Dell Networking N3000 stack, as all the 1Gb ports were directly connected – no traffic crossed the uplink ports to the Dell Networking N4000 fabric.
Networking N4000 switches, as all of the 10Gb ports were directly connected, no traffic crossed the uplink ports to the Dell Networking N3000 stack.
B Pool/volume placement: full test results Full test results: 1Gb initiator connecting to 1Gb targets versus 10Gb targets 22 Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays | BP1008
Full test results: 1Gb initiator connecting to separate speed versus mixed speed pools 23 Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays | BP1008
Full test results: 10Gb initiator connecting to 1Gb targets versus 10Gb targets 24 Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays | BP1008
Full test results: 10Gb initiator connecting to separate speed versus mixed speed pools 25 Best Practices for Deploying a Mixed 1Gb/10Gb Ethernet SAN using Dell Storage PS Series Arrays | BP1008
C Performance testing configuration Although the testing was performed previously, the recommendations remain the same as the architecture and functionality remain unchanged with regard to these tests. As a result, it was not necessary to re-run the tests in order to revise this document.
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