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Cloneranger
Hot Shot
Hot Shot

Best ISCSI setup for load balancing/failover?

Hi guys,

I am sure you can help me,

I am new to ISCSI SANs having always used FC before,

What would be the best pratice iyo for this setup?

I have an Equallogic PS3600x and am due to recieve another soon,

I have 8 vmware hosts, to connect to it,

I plan to use a dedicated ISCSI lan,

I terms of connetivity I have 4 gigabit ports free in each host for connection to the ISCSI LAN,

I have a pair of Cisco 4948s to handle the switching, I have configed these for flow control and jumbos, - not sure if I should stack these?

My first concern is resiliance, then performance,

So I would like some sort of multipathing going on, as I had in the MSA1000s I am replacing,

I have also heard on here that the MS ISCSI initiator outperforms the VMKernal one, thoughts?

Should I create two vSwitches with two links in each? and patch one link into each pSwitch?

There are quite I few combinations of connectivity between the 4948s and the guest OSs, any kind of insight would be much appreciated,

TIA guys,

Aaron

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8 Replies
doctormiru
Enthusiast
Enthusiast

Hi

At least you don't need the MS iSCSI Initiator to use iSCSI storage for your VMs.

The usage of multipathing within iSCSI storage environments is only supported using hardware iSCSI adapters. The esx SW-iSCSI initiator does provide any multipathing configuration. See the HCL for supported iSCSI HW adapters.

Using the ESX SW initiator increases CPU load of your SC and the throughput is not as high as with HW offload engines.

regards

Michael

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Cloneranger
Hot Shot
Hot Shot

Hi,

I thought the Hardware initiators were only experimentally supported in ESX?

Or am I lagging behind in my ISCSI knowledge?

Surely if your LAN connection is resiliant your ISCSI storage is resiliant?

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5474
Enthusiast
Enthusiast

Hardware iSCSI adapters are now fully supported. Check QLogic and VMware HCL for the list of the HBAs

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pdrace
Hot Shot
Hot Shot

Make sure your server vendor supports third party ISCSI HBA before investing in them. I found out the hard way that HP does not and doesn't have a rebranded part yet.

IBM has a rebranded product, I'm not sure of Dell's support policy but I will be checking in to it once Barcelona is widely available.

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mrcreosote
Contributor
Contributor

We use the ESX SW-iSCSI initiator and, at the moment, it is performing very well although the hosts aren't under a huge load.

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Peter_Frazer
Contributor
Contributor

Let's be clear about Vendor support. HP will cover parts under HP branding either as part of the Server Warranty when purchased with the server or the part's own warranty if purchased seperately or covered by a carepaq (extended/enhanced support). When buying 3rd party products, be aware that while it may be supported from the sense that HP will verify that the part will not cause problems under most scenarios, technical support and repair/replacement lies with the manufacturer or distributer of the product. Hence, if you buy a QLA-4050c/4052c iSCSI card, that card is verified by HP and VMWare from a hardware perspective, but is supported by the distributor (InfoX and the like) or manufacturer (QLogic).

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pdrace
Hot Shot
Hot Shot

I have talked to HP extensively and they have never claimed to have verified that the QLA-405X cards will work in their servers, even after I told them that future server purchases for VMWare may be from another vendor due to the lack of support for any ISCSI HBAs.

I was told quite clearly that if it isn't in the Quickspecs it is not supported.

This was conveyed to me by VMWare after they consulted with HP.

VMWare would not provide support with ISCSI problems with the QL4050s installed in HP servers based on their statement.

It seems they are behind the times in the ISCSI market, I have asked if and when they plan to release a rebranded ISCSI HBA that is supported. I've never gotten any type of response to that question.

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smoke455
Contributor
Contributor

Surely if your LAN connection is resiliant your ISCSI

storage is resiliant?

I don't think this ever got answered. I thought I had something working with two IP paths to our iSCSI appliance, but it has failed on me a couple of times durning the night. The first IP address stops responding and it waits 90 seconds to rollover to the other IP address. My problem is my 2 NetWare servers and 1 Win2k3 server running progress database freeze hard within the first 10 seconds of the lost connection.

I'm having to look at moving back to local storage now - there seems to be no good answer for the iSCSI redundant failover

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