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I need to implement some more drive space and am planning on using a ReadyNAS 2100. 4 TB, hot swap disks, etc.

The device can do NAS or iSCSI. I’m debating if I should setup an iSCSI target to one of my Servers and use DFS to populate and create the share.

OR

Use DFS to create a root share and then create a link to the big chunk of disk space.

What are the draw backs of going iSCSI? Does it take a lot of overhead in terms of CPU\RAM on the server that’s attached via iSCSI?

Can I create the Root DFS on my Domain Contoler or is that not a good idea? There would be no data store on it, just the actual DFS pointers.

Has anyone done what I’m thinking of doing?

As always the advice you all give is much appreciated.

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Hi Chads,

I have a ReadyNAS and only use iscsi to connect my ESXi servers which in turn present the disk to windows machine.

You can connect direct with windows but I have not done this in a production environment.

If you use software iSCSI there is a performance overhead that you won’t get if connecting to a share on the readyNAS , do you have hardware iSCSI on the servers? If so I would probably go down that route.

Cheers Hubba

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While you can setup any share with DFS, only Windows servers can replicate. So if you’re planning on using that feature (and it’s one of the best features of DFS) then you pretty much have to use iSCSI.

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Martin9700;

My worry is that if I link iSCSI to my Domain Controler to create the disk and share it for DFS purposes what hit will my DC take? It’s a virtual machine so I could always put more resources to it. Currently it’s pretty light on resources I’ve given it (1 CPU, 512 RAM, Server 2003 R2)

If a person had to move or remap the iSCSI target in the future can this be done with little interuption to the end users? All the data would remain intact on the isCSI target, just having a different machine pick it up.

Thanks again for your input, much appreciated!

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Chads wrote:

Martin9700;

My worry is that if I link iSCSI to my Domain Controler to create the disk and share it for DFS purposes what hit will my DC take? It’s a virtual machine so I could always put more resources to it. Currently it’s pretty light on resources I’ve given it (1 CPU, 512 RAM, Server 2003 R2)

If a person had to move or remap the iSCSI target in the future can this be done with little interuption to the end users? All the data would remain intact on the isCSI target, just having a different machine pick it up.

Thanks again for your input, much appreciated!

What kinds of overhead are you expecting for iSCSI? iSCSI is just SCSI over TCP/IP, so the overhead is basically the same as any network communications. Your CPU does pretty much nothing. Yes, you can get iSCSI offloaders to make it even less, but if iSCSI is taxing your CPU you’ll already be having issues with your box.

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Scott Alan Miller wrote:

Bingo! That’s exactly the informiton I was looking for. Thanks for all the info. So far it’s been working well in my tests and I’ll be working with my first Go Live department hopefully this week.

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Glad to help :slight_smile:

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Scott is the guru on storage but I will add this…I have a FreeNAS box setup running through iSCSI to an App server and I’ve experienced 2 drawbacks.

  1. If my internet connection drops, I also lose connectivity to the FreeNAS box

  2. Every time I reboot either the FreeNAS box or the App server, I have to redo all the shares for that drive letter.

Other than that, its one of the best decisions I’ve made for my network.

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schooner44 wrote:

Scott is the guru on storage but I will add this…I have a FreeNAS box setup running through iSCSI to an App server and I’ve experienced 2 drawbacks.

  1. If my internet connection drops, I also lose connectivity to the FreeNAS box

  2. Every time I reboot either the FreeNAS box or the App server, I have to redo all the shares for that drive letter.

Other than that, its one of the best decisions I’ve made for my network.

Good point. I haven’t rebooted either yet since mapping them out but will for sure run it thru that test.

I’m moving my data off a Novell server and I can’t believe the speed difference (for the good) compaired to Novell. The Novell server is a virtual machine, maybe that has something to do with it. I was seein maybe 4-5 times the speed in just raw file coping between Novell and iSCSI(ReadyNAS \Windows 2003 box.).

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Virtual machines often have I/O bottlenecks. Not necessarily, but common design does not lean towards I/O performance, so that could easily explain it.

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schooner44 wrote:

Scott is the guru on storage

And your check is in the mail, sir.

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