ISCSI Initiator - Raid1 mirror?

I have a Microsoft Server 2008 box that is connected to two ISCSI drives using ISCSI Initiator. How do I setup a RAID1 mirror with the two ISCSI drives using ISCSI Initiator?
lineonecorpAsked:
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jakethecatukCommented:
Have you connected to your iSCSI SAN yet?

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lineonecorpAuthor Commented:


Yes, The Server 2008 box has been connected two both ISCSI SAN boxes and displays the drives in disk manager. One of the San ISCSI drives is being used in a cluster setup and it won't let me convert to a dynamic disk. Is there a way around that?
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jakethecatukCommented:
You can't use your quorum disk unfortunately. If you have used a big disk for quorum, then you better off destroying the cluster and provisioning a small LUN for your quorum (about 1gb will be enough).

To create a software mirror, right click on one of the drives and choose new mirror. A wizard will start which is very simple. Click thru and accept the warning about basic to dynamic disks. That's all there is to it.
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lineonecorpAuthor Commented:
I'm not quite following. Are you saying I can't convert a drive to dynamic if it's in a cluster?
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jakethecatukCommented:
No. Once a disk has been taken by the cluster to act as the quorum, you can't use it for anything else. So if you have a 100gb LUN and the cluster has it, then you have lost 100gb of storage.

How many iSCSI LUNS have you presented to your cluster and what sizes are they?
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andyalderCommented:
MSCS does not support dynamic disks, you can use Veritas Volume Manager or whatever they've renamed it to instead if you really want dynamic disks in a cluster. Dynamic disks really don't belong on a SAN, they'll give all sorts of problems.
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jakethecatukCommented:
[andyalder quote]MSCS does not support dynamic disks, you can use Veritas Volume Manager  or whatever they've renamed it to instead if you really want dynamic  disks in a cluster. Dynamic disks really don't belong on a SAN, they'll  give all sorts of problems[end quote]

The OP isn't using MSCS.  If you go back thru the OP's other questions you'll see what he's up to.
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lineonecorpAuthor Commented:

One of the two SAN boxes is running a 320 GB and is dedicated to the cluster. I want to configure this san as a raid1 with another, what's the best way to do this?
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andyalderCommented:
What SAN boxes have you got?
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jakethecatukCommented:
[lineonecorp quote]One of the two SAN boxes is running a 320 GB and is dedicated to the cluster. I want to configure this san as a raid1 with another, what's the best way to do this?[end quote]

OK - so SAN 1 has a 320gb disk that you want to present to your HYPER-V cluster for use.  I'm going to assume that your other SAN has similar storage

Well, using your SAN management software, you going to need to partition the 320gb into useable chunks for your environment.  You could do the following: -

Partition 1 = 1gb
Partition 2 = 300gb

Present partition 1 to both 2008 Core servers as this will be the cluster resource quorum.  This disk MUST BE BASIC.

On your second SAN, create a partition of 300gb.

If you want to create a software mirror on node 1 of your 2008 Core cluster, present both 300gb partitions to your server - do not present the partitions to both servers as it won't work.
On your 2008 core server, create the mirror set as described in ID:29888020.  This will be a dynamic disk and will only be visible to node 1 of your cluster as a local disk - you will not be able to add this disk to your cluster.


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lineonecorpAuthor Commented:
I'm not quite sure if your understanding my current setup so I'm going to try and explain it again.

I have a Server 2008 box setup as a domain controller that manages the cluster server which consist of two Server 2008 core boxes. Let's say the computer names for the core boxes is CLUSTERNODE01 and CLUSTERNODE02. I also have an Open-E san that is setup as an ISCSI drive partition using a 320GB drive. both CLUSERNODE01 and CLUSTERNODE02 can both see the 320GB drive (I added the drive using ISCSI initiator on both computers). I then configured the Server 2008 box that manages the cluster server to cluster CLUSTERNODE01 and CLUSTERNODE02 with the 320 GB drive. I now want to add a second san box with a 320 GB drive that mirrors with the first SAN that is being used with CLUSTERNODE01 and CLUSTERNODE02. Can't I just added the second san to both CLUSTERNODE01 and CLUSTERNODE02 using ISCSI initiator again then configure both san drives as a dynamic disk and mirrored in disk manager? I don't want to re-partition the working san that is setup in the cluster.
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andyalderCommented:
Wouldn't you be better off mirroring with Open-E DSS Volume Replication?
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jakethecatukCommented:
[lineonecorp quote]I have a Server 2008 box setup as a domain controller that manages the cluster server which consist of two Server 2008 core boxes. Let's say the computer names for the core boxes is CLUSTERNODE01 and CLUSTERNODE02. I also have an Open-E san that is setup as an ISCSI drive partition using a 320GB drive. both CLUSERNODE01 and CLUSTERNODE02 can both see the 320GB drive (I added the drive using ISCSI initiator on both computers). I then configured the Server 2008 box that manages the cluster server to cluster CLUSTERNODE01 and CLUSTERNODE02 with the 320 GB drive. I now want to add a second san box with a 320 GB drive that mirrors with the first SAN that is being used with CLUSTERNODE01 and CLUSTERNODE02. Can't I just added the second san to both CLUSTERNODE01 and CLUSTERNODE02 using ISCSI initiator again then configure both san drives as a dynamic disk and mirrored in disk manager? I don't want to re-partition the working san that is setup in the cluster.[end quote]
Ah...see where you're going now lineonecorp.  You can add the disk, but clusters only support basic disk volumes and to do a software mirror requires the use of dynamic disks.  I'm guessing that you're looking at doing some form of fault tollerance by having the data on both SANS using mirrors at the cluster level.

Depening on the version of Open E SAN you have will depend on the way forward.  The standard version of DSS 6 supports asyncronous data replication which is probably what you need to be looking at - http://www.open-e.com/products/open-e-dss-v6-lite/comparison/
 
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lineonecorpAuthor Commented:
I'm using Open-e Lite (free version) which doesn't support the asyncronous data. Is there a way to still accomplish what I want done without purchasing the standard version?
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jakethecatukCommented:
OK.  I'm guessing that this is a production environment and you don't have much budget to buy the full product (it's only $895).

I've got a few ideas on this so I'll come back to you soon.
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jakethecatukCommented:
Can you do me a favour...can you post a screen shot of the storage section under failover clustering - would like to check something on your config.
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jakethecatukCommented:
Got a possible solution for you on how to achieve a level of redundancy from using both SANS.

As we've already established, you can't mirror the disk under HYPER-V and present them to the cluster as that doesn't work.  Also, in order for clustering to work, you're going to have to present the disks to HYPER-V cluster and store your data on there.

So, here is a possible solution for you.  Have a look at the attached image and you will see two SANS and two servers.  In the image, I've shown two iSCSI LUNS presented to each server but that is just an example.

The iSCSI LUNS are added to the cluster as failover clustered storage which will allow both servers to have access to the data and you can fail over the disk resource between HYPER-V hosts.

The virtual machine is configured with software mirrored drives and for this to work, you will need to make sure that each VHD is set to be saved to a different iSCSI LUN.

As solutions go, this is far from ideal as it has far too many compromises in it for comfort, but you will have an element of redundancy.

For this solution to work, you are better off having small iSCSI LUNS that are dedicated to each virtual machine.  This will allow you to fail over individual virtual machines between HYPER-V hosts.
cluster.png
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lineonecorpAuthor Commented:
Thanks for going the extra mile. Your picture is what we have now as far as the two Open-E (Lite) SANs. Right now the disks in the two SANS show up in disk manager but as we noted we could not mirror.  If I read what you are saying I should:

add a second drive to each HyperV server and sofware mirror - assuming I only want a C drive in the VM's as opposed to the C and D that you have - - this way my C or OS volume is mirrored.  I will then use the SANs as data volumes.

I then 1)IP explore and find the two SAN devices and their respective drives (the ones that now show up in disk manager) and  and 2) designate those drives as  paired failover clustered storage - I assume that is some configuration choice in cluster manager.
Question: Don't I still need a quorum disk of some sort? Note it is not a problem for us to add an additional drive to each SAN as we are nowhere near the 2 TB limit. So I was thinking I could leave everything as is now with the current SAN drives showing up in disk manager and just add two extra drives - one to each SAN -  and make those the failover clustered storage you recommend.

As another possible alternative I notice that  that there is something that comes with the Lite version called  Synchronous Volume Replication. It sounds a bit problematic as far as performance but it does do a type of redundancy that might be ok in some file server type environments. Any thoughts on it?
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lineonecorpAuthor Commented:
I think the feature you are referring to is Shared Cluster Volume?

http://www.servercare.nl/Lists/Posts/Post.aspx?ID=89
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lineonecorpAuthor Commented:
jake,

I have added a second SAN to my setup with a 320 GB drive and configured it as an ISCSI drive. I added the drive as a shared cluster volume and accessible through both my CLUSTERNODES. What is the next step? Where is the redundancy with this setup?
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lineonecorpAuthor Commented:
Still thinking this over?
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jakethecatukCommented:
Can you post screen shots/simple drawings of your config - it will help me see where you are.
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lineonecorpAuthor Commented:
Let me work with your diagram for ease of communications as it may in fact address all the issues.  I'm more interested on a way to do things than the way I might be trying.

In your diagram if for reason 'left' Core Server 2008 goes down,  what happens to the VM?  Will it will fail over to a VM on the 'right' Core Server?  And when I bring 'left' Core Server back to life, will it then be    ready to do the same if 'right' Core Server goes down?

Ditto for left and right SAN's - what happens if 'left' SAN goes down?  Then what happens when I bring it back to life?

Finally throughout all of this where is the data and will it be available throughout both of the above failed situations - failed Core Server and failed SAN?

 Basically I would like to set up one SAN in one corner of the office, the other in another corner, one Core Server in the third corner and one Core Server in a fourth corner and have the system keep chugging away if 1 of the Core Servers or 1 of the SANs goes down or even if a pairing goes down.





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lineonecorpAuthor Commented:
Sorry I got sidetracked from this project so I haven't pursued. Were my questions in the last post clear? If you wish I can just close this off and award points and ask them in another post as you've already put in quite a bit of time on this and you can respond to the other post instead.
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jakethecatukCommented:
I got sidetracked as well :)

OK...if you have two network switches and you connect both servers to both switches from different NIC's and the same with the Open-E SAN's again making sure you use two NIC's, then in theory, you will have near total redundancy.    You will need to configure the iSCSI targets with two IP addresses and each W2008 server will need to have both IP addresses added under iSCSI initiator settings.

However, if you only have the lite version of Open-E San then you can only have one NIC which will obviously cause problems as you will have a single points of failure on the SAN side of things.

Obviously, there will still be single points of failure - power and building to name two.

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lineonecorpAuthor Commented:
Thanks for coming back into this and I'm also happy to hear what you had to say as far as redundancy - you've basically told me what I was hoping to hear.  Mucho thanks.
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