VMware Solutions Discussions

iSCSI broadcasting - Is this normal?

djaquays0

Here's the setup.  We have an ESX Host, our ArcServ manager and 2 NetApp FAS2050s (3 filers total) on a vlan used for iSCSI traffic.  Currently, we're only using iSCSI as the protocol to transfer our physical server backups to the netapp.  The problem is, any traffic that is sent across this VLAN is ALWAYS broadcast to every port that is associated with this VLAN.  Is this normal behavior?  Our storage networks are compartmentalized enough and our current iSCSI usage is low enough that this isn't a crtical issue at this point.  I'd prefer to assume this isn't normal and am wondering if anyone else has seen this behavior and has any idea what might be causing it?

6 REPLIES 6

BrendonHiggins

Hi

How do you know it is being 'broadcast', are you getting errors in logs or reading dumps with wireshark?

Bren

djaquays0

After setting up the iSCSI connections, we did a fairly large dump of all of our current physical server backups to the netapp.  During this transfer we noticed in our network usage monitor that every port associated with that VLAN had exactly the same amount of traffic going to it for the duration of the copy.  We then verified what we believed was happening using wireshark on a separate port assigned that VLAN.  The packets properly show the SRC and DST mac addresses and IP addresses for the transfers.

As far as we can tell, our iscsi vlan is setup exactly the same as our nfs vlan, but we see no issues with the nfs ports.  I believe my coworker opened a ticket with Extreme Networks regarding this and we'll continue to hunt for the issue.

amiller_1

Just curious....did you ever find anything out as to what was happening here?

djaquays0

Sadly, no.  We have a case open with Extreme and have been passed around engineers who all seem to have no idea why this is happening.

amiller_1

Doh.....sorry to hear it....

In cases like that, I'll sometimes just build a switch config from scratch (from absolute scratch -- no macros/wizards/auto configuration -- so I know what each and every config line does).

amiller_1

Definitely not normal -- I'd check your physical switch config and/or your ESX vSwitch config. Feel free to post config details if you'd like some feedback...

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