Tag Archives: vcap

Storage DRS Configuration – Architectural Decision making flowchart

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I was speaking to a number of people recently, who were trying to come up with a one size fits all Storage DRS configuration for a reference architecture document.

As Storage DRS is a reasonably complicated feature, it was my opinion that a one size fits all would not be suitable, and that multiple examples should be provided when writing a reference architecture.

A collegue suggested a flowchart would assist in making the right decision around Storage DRS, so I took up the challenge to put one together.

The below is my version 0.1 of the flowchart, which I thought I would post and hopefully get some good feedback from the community, and create a good guide for those who may not have the in-depth knowledge or experience, too choose what should be in most cases an appropriate configuration for SDRS.

This also compliments some of my previous example architectural decisions which are shown in the related topic section below.

As always, feedback is always welcomed.

I hope you find this helpful.

* Updated to include the previously missing “NO” option for Data replication.

SDRS flowchart V0.2

Related Articles

1. Example Architectural Decision – Storage DRS configuration for NFS datastores

2. Example Architectural Decision – Storage DRS configuration for VMFS datastores

Giving Back to the VMware community

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After achieving my VCDX in Toronto mid last year (2012), one of my goals was to start blogging and giving back to the VMware/Virtualisation community which I wrote in my About Me post back in April last year.

Over the last year I presented at multiple VMUG events , contributed to community podcasts and kicked off this blog (CloudXC). I also got more involved with Twitter and VMware Communities forum.

I have also helped a number of VCDX candidates with mock panels and submission reviews and I am very pleased a number of those candidates have been successful.

I am pleased to say I have thoroughly enjoyed getting more involved with the community, and have met a lot of great people and learnt lots of new things along the way.

Today I received notification that along with 574 others, I was awarded the title of vExpert for 2013. (vExpert Awardees announced here)

Just like achieving VCDX, earning the vExpert title for me is just motivation to continually keep improving my skills and adding value to the community.

Thanks to everyone involved with the vExpert Program and I look forward to continuing to contribute too this great community and hopefully get another vExpert gong next year.

Congrats to everyone else who was awarded vExpert for 2013!

vExpert_pre2013_new

 

 

Example Architectural Decision – Jumbo Frames for IP Storage (Do not use Jumbo Frames)

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Problem Statement

When using IP based storage over a converged 10GB network, should Jumbo Frames be used?

Requirements

1. Fully Supported storage

2. Maximum vSphere environment availability

3. Maximize performance where possible

Assumptions

1. Converged 10GB Network which is highly available

2. Two (or more) 10GB connections per ESXi host

Constraints

1. No dedicated network for IP storage traffic

Motivation

1. Simplify the environment

Architectural Decision

Do not use Jumbo Frames

Justification

1. Reduce the complexity in the environment for initial implementation

2. Simplify ongoing support / troubleshooting

3. For a Jumbo Frame to be transmitted without fragmentation, All devices end to end must support and be configured for Jumbo Frames

4. While there can be performance benefits of Jumbo Frames for IP Storage this is not generally seen across the board and depends on I/O types

5. Ensure IP storage packets are not fragmented or dropped by mis-configured devices or devices that do not support Jumbo Frames

6. Storage performance for the virtual environment will generally be constrained by the storage array controllers not the storage area network

7. Ensure packet fragmentation does not occur as all devices support a default MTU of 1500

8. Increasing the MTU will decrease the number of packets required for the same bandwidth but where the bottleneck is throughput (bytes) there will be minimal/no benefit

9. Jumbo Frames will only assist where the network is constrained at an interrupt level

Implications

1. IP Storage may have reduced performance in some circumstances compared to what Jumbo Frames may offer

Alternatives

1. Use Jumbo Frames

Relates Articles

1. Example Architectural Decision – Jumbo Frames for IP Storage (Use Jumbo Frames)

 Contributors

Thanks to Rob McNab (IBM) and Peter McCrystal (IBM) for their input into this example architectural decision.