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Configuring PowerVault MD3620i for Redundancy & Multipathing
I’ve got a PowerVault MD3620i Unit with dual controllers. I have all four NICs on the same VLAN, with sequential IP addresses (192.168.1.50,51,52,53). I have 2 disks defined, one assigned to RC0, and one assigned to RC1. If I provide the server’s ISCSI initiator with the IP of RC0 (192.168.1.50) the server can see both disks but any attempt to access the disk owned by RC1 returns an error. On the other hand, if I provide the initiator with the IP of RC1 (192.168.1.52) then the reverse is true, and I can access the disk owned by RC1, but not the disk owned by RC0. If I fail the disks from one controller to the other then they become accessible or inaccessible depending on what controller they’re assigned to.
It doesn’t matter if I provide the initiator with multiple IPs, one the first IP supplied seems to matter.
This behavior doesn’t seem normal to me. Am I doing something wrong?
Dev Mgr
9.3K Posts
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June 2nd, 2011 13:00
Set the iSCSI IP addresses back to the factory defaults and match your server NICs to those 2 (different) subnets.
To get an idea of the cabling and IP schema, check out this page.
mrokkam
154 Posts
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June 8th, 2011 09:00
The MD3620i is what I call an active/active/passive array. What this means is that both controllers can do I/O... but only 1 of them can access a single Virtual Disk at a time. So, the behavior that you are seeing is as expected...but you seem to not have the host multipathing driver installed. The multipathing driver will consolidate all of the disks into a single disk so that you can access it from any RC.
Another potential problem is that you are only setting up discovery sessions to one controller. You should set up sessions to both controllers. If using windows or linux, you can use the MD Configuration Utility to configure the iSCSI sessions. You can also find iSCSI config guide in the owners manual...linked below.
What OS is this?
You should use the Resource DVD and install the array specific host drivers. For windows, the MD3620 uses MPIO and for Linux, it uses DM and these need to be installed. ESX and XENserver have built-in drivers.
You can find specifics of configuring MPIO and DM in the owner's manual:
ESX details are in the ESX deployment guide available @ www.dell.com/md3600i
Thanks,
Mohan
spgsit
185 Posts
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December 17th, 2011 13:00
I have a question here:
MD3600i with dual controllers, connecting to two isolated PowerConnect 54xx switches (tripple fibre tunk between switches)
3 x ESX5i servers with two physical iSCSI Qlogic HBA in each
If considering only that setup I could easily do different subnets
But I also have Eqallogic PS5000E array (also dual controller)
But PS5000E has active-passive controller presenting a SINGLE group IP (and not port IP)
No subnets involved here then
So if I use both arrays (and both I must) I see no way (with my hardware) to do it "right" as per Dell recommendation
(if I have subnets, then I have no redundancy to PS5000E from ESX servers, as only 1 HBA can be on the same subnet as PS5000E)
Anybody having any suggestions?
z900collector
13 Posts
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August 21st, 2012 16:00
I see this as well as one of my configurations is very similar, but I am always able to access a path via VMWare, however if a Windows system is given direct access to the LUN via the wrong controller the LUN wont initiaialize in disk manager until I swap the ownership of the LUN to the other controller. I think ESX seamlessly handles this (but the warning light comes on the front indicating a path violation across controllers).
I think the key is to split the IP range into two, put them into two VLANs on your switch and make sure you dont violate the controller pathing (most of the PDF guides on the web show this as the classic scenario but they dont actually explain the warning light coming on if you dont). The guides all show this and fundamentally what you and I have done works but the controller reports a tresspass error/warning when a disk has to be accessed across controllers.
Sid
Dev Mgr
9.3K Posts
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August 21st, 2012 19:00
You need to install MDSM (or at least the host software) on any Windows system that you connect to the MD-series SAN.