powerconnect 62xx iscsi QOS

Actually, for the EqualLogic arrays we don’t recommend using the iSCSI optimization or CoS in most situation.  The switches should be solely dedicated for the iSCSI subnet, and management features.

You want to make sure the switch has:

no iscsi enable

The cos command sets the quality of service profile that will be applied to traffic flows. If iSCSI frames comprise most of the traffic passing through the switch, the system provides optimal throughput when all traffic is assigned to the default queue.

In general, the configuration is as follows:

Switch Firmware should be v3.3.4.1 A28 (or newer)

- Do not use the default VLAN for iSCSI traffic (the default vlan does not handle jumbo frames reliably)

- Turn Flow Control ON

- Turn Spanning Tree PORTFAST ON

- Turn Jumbo Frames ON

- Set Jumbo to 9216

- Turn iSCSI Optimization OFF

The configuration Guide and Configuration Portal provide the detailed setup instructions:

http://en.community.dell.com/techcenter/storage/w/wiki/2639.equallogic-configuration-guide.aspx

http://en.community.dell.com/techcenter/storage/w/wiki/3615.rapid-equallogic-configuration-portal-by-sis.asp

-joe

Joe, 1st thanks for the reply. I'm a bit confused because i been reading on various DELL docs that the great thing about the powerconnect 62xx series is the fact that it configures itself for ISCSI support and to enable ISCSI optimization. Also the enable ISCSI command basically sets up what you recommend above, jumbo frames and RSTP port fast on initators/SAN ports etc. Can you explain a little why i should manually do this instead of having the ISCSI optimization do this for me. Note that i will use these switches for ISCSI traffice only.

Various DELL docs recommend this to enable ISCSI optimization.

i.dell.com/.../equallogic-iscsi-optimization-powerconnect-switches.pdf

en.community.dell.com/.../3615.rapid-equallogic-configuration-portal-by-sis.asp

Please advise

Paul

In addition to the links that Joe sent, I also have a post that addresses building a pristine configuration for a stacked set of 62xx series switches.  You can find it here:  http://vmpete.com/2011/06/26/reworking-my-powerconnect-6200-switches-for-my-iscsi-san/ 

- Pete

Paul,

Regarding the one link you provided, i.dell.com/.../equallogic-iscsi-optimization-powerconnect-switches.pdf

This is an older document compared to the link I sent out (scroll down to Step #3, and select the “PowerConnect 6224 or 6248 (Sept 2012)” configuration.

The main reason for the shift away from using the iSCSI optimization features is that although it has simplified setting up iSCSI, it’s not a “one size fits all” solution.  We have found that manually configuring iSCSI with the settings is a more reliable setup, and provides improved performance.

Pete (a.k.a. sketchy00), solution is also a good example of manually setting up for maximum performance.

-joe

thanks Joe/Pete for this. Joe i will follow your advise on the original post. It's too bad DELL can't remove or update the old PDF to reflect the current best practices.

paul

Paul,

Your complaint is one of the reasons why I ended up creating a post to give others an absolute point of reference.  To no fault of anyone's, there was some conflicting information that stemmed from best practices at the time, firmware at the time, etc.  Some of the source PDFs, etc. were stored in non-Dell locations.  I've ended up using the settings described in my post in many deployments and things have worked perfectly.  Others have shared with me the same experiences.

Just one more point to help clarify why it is recommend to manually set up iSCSI, versus using the optimization feature:

The optimization ability of the switch will only detect active EqualLogic arrays attached directly to its ports through LLDP packets received by the switch with the proper Chassis ID for EqualLogic.  If the match is found, the switch recognizes the existing of an EQL array on that port and configures for iSCSI.

However, any of the Host iSCSI connection (hosts connected to the iSCSI VLAN ports) are not configured for iSCSI and need to be manually configured per the configuration Portal settings.

So it just makes life easier to manually configure a range of interfaces in the iSCSI VLAN, instead of having to manage two sets of configurations.

Also to clarify, that the document you referenced is not outdated, however, the configuration portal is the best place to find EqualLogic configuration specific information.

-joe

Joe, thanks again