Monday, July 20, 2009

Exploring iSCSI for the 1st Time - An Easy Intro for new beginners

Ehlo All,

So, I have to admit it. I'm an iSCSI SAN newbie. While people are afraid to repair an Exchange database via eseutil, install and configure the SSL certificate for Exchange 2007's Outlook Anywhere, routing groups, and configure DNS TTLs, I'm very comfortable with all that. On the other hand, iSCSI, that's a foreign language to me. With terms like target IQN, LUN mapping, SCSI Serial No, SCSI ID, blockio, etc, it's understandable, at least to me. To summarize, iSCSI target means iSCSI sharing server, iSCSI intiator means client.

So, I finally had 2 scenarios that warranted that I setup an iSCSI environment. I needed more storage capacity in my ESXi environment and one of my "traditional" Windows 2003 Server. Traditional meaning a physical server. So, while adding internal storage is possible, it would have been a real pain since all the slots were filled. So, I had an existing Windows 2003 Server with a LOT of extra storage (4.4 trillion bytes, or 4.4 TB). I made a BIG mistake when quoting storage for it, so I have way to much storage on one server. So, how could I reliabily share storage over the network and appear as a locally connected drive letter on boot, iSCSI!

I considered 3 options, since I needed it to run on top of an existing Windows Server OS.
1) formerly LeftHand Networks (aka LHN) SAN VSA (VMware appliance). LHN was a hardware and software SAN vendor. They use to offer a free* VSA 8.0 which included a management application to configure the SAN solution. *I searched, and could not find the free unlimited usage VSA option anymore, so I would not recommend this approach.
2) open-source/free OpenFiler (aka OF) SAN (Linux, VMware, 2 Xen options, and more). This is really designed for the Linux crowd, some experience SAN users, or diligent admins.
3) Starwind (Windows). Designed for the SAN newbie and offers a free option.
[updated Starwind URL to correct one as per below comment.]

LHN VSA: I had LHN's VSA working in a cluster replicating file data, but decided I only wanted one VSA running for this. But for some odd reason when I removed it from the cluster, it would not let me add volumes to it. I spent a few hours troubleshooting this, but it looks like HP (which acquired LHN) dropped the free VSA option and the great support website. So, I decided to "drop" VSA as an option as well.

OF: I downloaded the OF 2.3 VMware VMDK, unzipped it, and placed it in a VM directory and it booted right up within VMware Server 2.0.1. Changed the IP and password via the web interface and ran the web based updater. Very clean interface, but very few wizards and little documentation. They also charge $60 for the manual. I guess the manual is not open-source. A bit frustrating especially since this is a community product. I would normally donate to the cause, but I'm not a fan of their business model approach. So, I used the following 2 websites and 1 OF forum posting to understand what I needed to do. Not surprisingly, that forum poster left OF and went to Starwind. OF is really designed for bare metal computer installs with your own hardware RAID already setup. But if you know the limitations, it can work for other purposes.

Overview with screenshots of OF iSCSI configuration
http://www.petri.co.il/use-openfiler-as-free-vmware-esx-san-server.htm

Overview with screenshots of ESX iSCSI connection to OF
http://www.petri.co.il/connect-vmware-esx-server-iscsi-san-openfiler.htm

Bonus - Good Overview of iSCSI and OF (connecting with Windows Server iSCSI initator)
http://www.montanalinux.org/openfiler-iscsi.html

At the end of the day, OF is serving iSCSI storage in my environment.
- Windows 2003 R2 Server running 3Ware 9550SXU-4LP hardware with RAID 5 configuration
- VMware Server 2.0.1 running on above Windows 2003 R2 Server
- OpenFiler VM configured for 2 additional virtual hard drives, each 100GB which are in a OF software RAID 1 setup. Protect against software corruption.
- ESXi handling the iSCSI initator to the above server (but you could easily make Windows the iSCSI initator which I plan to do in a few weeks. Microsoft offers for free the iSCSI initator.)

-Ben

2 comments:

Anonymous said...

I can say, that official site of Starwind is http://starwindsoftware.com and its powerful enought to build complicated iSCSI storages.
John.T

Ben Serebin said...

Hello John T,

Thanks for the info. You are correct on the URL.

I should have clarified that Starwind offers a very easy to use implementation of iSCSI on top of the Windows platform.

-Ben