iDRAC - shared network question

Question

I'm low on network ports in my computer room and want to set up the iDRACs to use the shared network port instead of a dedicated port. If I do this, will the iDRAC work when the server is turned off? What features do I lose if I use the shared network port instead of the dedicated port?

Daniel My · Accepted Answer

Okay, I'm still trying to hunt down a server to test with. I found something else to check while we wait. Make sure your switch is capable of autonegotiating speed on the interface connected to the LOM/s. Let me know what speeds the switch is capable of.

When the server has AC input power applied but is powered off, LOMs typically negotiate down the external link speed for reduced power consumption while still supporting Wake-on-LAN and/or shared network ports. These re-negotiations can create a momentary external link loss which may or may not interrupt any active remote management connectivity. If a connected switch is configured in a way to not allow for this dynamic speed negotiation, then remote management connectivity may not be available when the server is powered down.

Daniel My · Answer

Hello Kevin

Yes, it will still be accessible when the server is powered down. The primary negatives are that the available bandwidth for applications on the NIC port that is shared will be reduced because part of it will be segmented for the iDRAC. Also, if there is an issue with the NIC the iDRAC will be inaccessible. When updating the NIC firmware or applying changes to the NIC iDRAC connection will be lost.

Also, the dedicated port is a gigabit interface(100Mb on blades). It will be throttled down to 100 megabit when shared.(Edit: This is in regards to 12th generation iDRACs. 11th and earlier are all 100Mb)

Thanks

kevin79 · Answer

When you say it will be throttled down, are you talking the data that is transmitted through the NIC for the OS as well?

Daniel My · Answer

The iDRAC will only use a maximum of 100Mb of bandwidth on the shared port rather than the 1Gb it will use on the dedicated. This will also decrease the available bandwidth for the OS on that port, so both.

kevin79 · Answer

So will the OS have 900Mb instead of 1Gb?

kevin79 · Answer

I just tested an iDRAC with a shared card. When the server is off, I can't ping or connect to the iDRAC. Is there a specific setting that I need to configure? The server has the latest firmware (iDRAC - 1.95, BIOS - 2.7.4) and is running ESXi 5.1

Daniel My · Answer

I just tested an iDRAC with a shared card. When the server is off, I can't ping or connect to the iDRAC. Is there a specific setting that I need to configure? The server has the latest firmware (iDRAC - 1.95, BIOS - 2.7.4) and is running ESXi 5.1

To my knowledge there is nothing to configure. Which shared mode did you set it to? Did you specify a shared LOM or is it shared with failover? All of the documentation I have read states that the iDRAC 6 express includes power management features via web GUI. Those features include powering on the server. I have not tested this myself though.

Are you able to access it when the server is on? If we can't get it working then I'll try to track down a server with with an iDRAC express to test with.

Thanks

kevin79 · Answer

Yes, I can get to it when the server is on. It is set to Shared with Failover All LOMs. Changing it to just Shared produces the same results.

Daniel My · Answer

Thanks for the update! I'm curious, what speed did it negotiate to with the laptop?

kevin79 · Answer

I'm not positive but it looked like 100Mb. I didn't really look though since the pings worked.

kevin79 · Answer

I think that is it. I took a laptop down there and used a cross-over cable to connect to that network port and the iDRAC worked. I'll have to talk to my network guy on Monday. Thanks!

PowerEdge Hardware General

iDRAC - shared network question

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