AllBlack
Expert
Expert

Using multiple SAN solutions

Hi everyone,

I am reviewing our vmware environment and I have a question regarding multiple SAN implementations.

Currently we have diverse clusters and I am looking at combing these where possible.

In our environment we have two different SAN solution and this could be more in future.

We will be looking into storage virtualization but that is another story.

In the mean time I would like to know if it is ok to connect a host to more than one storage array?

Actually all hosts in cluster would probably have this configuration for obvious reasons.

Reasons for wanting to do this is obviously because we have them and also so I can mix workloads on the servers.

My fast or critical vmdks could be stored on the enterprise SAN while the entry level SAN can be used for less

critical VMs.

cheers

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10 Replies
mcowger
Immortal
Immortal

We already do this (span multiple arrays from multiple vendors)






--Matt

--Matt VCDX #52 blog.cowger.us
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dkfbp
Expert
Expert

Hi,

Go for it. It is possible. Try considering looking into datacore for storage virtualization. They are pretty cool when you have multiple SANS.

Best regards

Frank Brix Pedersen

Best regards Frank Brix Pedersen blog: http://www.vfrank.org
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java_cat33
Virtuoso
Virtuoso

Yes it's certainly possible, I've also done it. One thing to keep in mind if your fabrics are fibre, is that when connecting to multiple SAN's to retain redundancy with your fibre connections you will need more fibre ports on your ESX box (for example 4 fibre ports - 2 ports per SAN.).

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AllBlack
Expert
Expert

Thanks everyone.

We are using ISCSI.

Any of you spreading VMs over multiple SANs? Let's say your enterprise SAN contains high-speed SAS disks so you store, in example, databases on there but

use the other SAN for the OS or logs?

It might be a bit of an admin overhead...

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Rodos
Expert
Expert

You can share the resources across Datastores (aka SANs) but as you have mentioned there is a slight management overhead. Don't forget storage VMotion which can come in handy here, you can move disks between the two without downtime. But remember it does place a performance hit so you probably want to schedule it for non-peak periods.

Rodos

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Texiwill
Leadership
Leadership

Hello,

Yes it is possible. If this is FC-SAN then you will want to make sure your ESX Fixed/MRU settings are set properly. In general you want it set to fixed in a multi-SAN configuration. You can also use multiple iSCSI Servers from different vendors with no major issues. You may want a more robust storage network in use however. 1GB may not be enough for everything. But that depends more on what you are doing than what iSCSI Servers are in place. It is a bandwidth issue.


Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

Blue Gears and SearchVMware Pro Blogs: http://www.astroarch.com/wiki/index.php/Blog_Roll

Top Virtualization Security Links: http://www.astroarch.com/wiki/index.php/Top_Virtualization_Security_Links

--
Edward L. Haletky
vExpert XIII: 2009-2021,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
beckhamk
Enthusiast
Enthusiast

on the FC comment about the hosts needing more ports in a multi san environment. That assumes you had two more fiber switches. I thought you could just connect the other san to the same set of fc switches? Is that not possible?

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Texiwill
Leadership
Leadership

Hello,

on the FC comment about the hosts needing more ports in a multi san environment.

That assumes you had two more fiber switches. I thought you could just connect the other san to the same set of fc switches? Is that not possible?

THis depends on how your fabric is interconnected. Personally I have all SANs feed to the edge switches which eventually go to the hosts. Generally 2 FC-HBA ports are enough, but I have seen some with 4 FC-HBA ports or more that do not suffer any issues. When you have more FC-HBA you can zone SANs to specific FC-HBAs so that you do not have bandwidth or other issues.

Whether or not this is necessary depends on what you are doing within the VMs more than it depends on anything else. Quite a few people do not need more than 2 FC-HBAs. But remember zoning in very important you do not want to zone all your arrays to just one FC-HBA unless you are in a failover case. You need to by hand balance the load.


Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

Blue Gears and SearchVMware Pro Blogs: http://www.astroarch.com/wiki/index.php/Blog_Roll

Top Virtualization Security Links: http://www.astroarch.com/wiki/index.php/Top_Virtualization_Security_Links

--
Edward L. Haletky
vExpert XIII: 2009-2021,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
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williambishop
Expert
Expert

I do it every day, you shouldn't have any problems setting it up. We share IBM and EMC on our fabric, probably 30% of our environment use both arrays at the same time.

Ita feri ut se mori sentiat
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GiacomoEDP
Contributor
Contributor

We have a FC SAN Storage connected dual-path to 2 switch FC and 2 ESX 3.5 server enterprise even those with 2 HBA. We would like to expand our infrastructure by adding a second FC SAN Storage. The FC switch ports are still available for the new Storage.

See some anomaly or mistake?

The two hosts can see both SAN and then proceed with the migration of the disks of the machines guest?

Thank you,

Giacomo

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