[IkerSilva]

Greetings!

I was asking on other places, but I`m gathering the different opinions.
I`m working in the middle size business. We`re looking for shared storage I`m considering what iSCSI solution is better if compare of price and functionality - software or hardware? And what vendor is more reliable?

[zx10guy]

It's funny you should bring up this topic. I'm dealing with storage issues currently at my job. To be upfront, I am not a storage engineer. But after getting into the trenches of studying various storage technologies, I understand why these guys are specialized and why they get paid what they get paid.

First, off, I don't understand what you mean by software or hardware.

If you are looking for an iSCSI solution, keep in mind, there are various practices you have to do to make iSCSI work optimally. First, iSCSI is basically SCSI commands wrapped around by TCP/IP so it can traverse a network infrastructure. Because of this any host initiator you set up which mounts a iSCSI device needs to have what is called a TOE (TCP off load engine) capable NIC. If your host device does not have one, you will be taking a general performance hit as your CPU must now deal with the iSCSI overhead. Second, while many people debate how much an advantage it is, iSCSI has to fall under the constraints of your network parameters which means if you are traversing an Ethernet infrastructure (as most people are) you are now limited to 1500 byte frames. To get better data performance, you would have to invoke jumbo framing with the requisite requirements that go along with it. And finally, for iSCSI to perform its best and to keep network performance optimal, you need to isolate all iSCSI traffic by setting up a dedicated VLAN to only carry iSCSI traffic.

Microsoft has support for iSCSI natively via Windows Server 2003 and 2008. I don't know if they provide any drivers for workstation level connections. The drivers for 2008 are said to be better than the 2003 version. You typically don't share out iSCSI mounts to all workstations. You typically mount the iSCSI device via a server which then shares out resources.

When getting into storage, you need to understand the basic concepts of RAID, IOPS, file or block level I/O, transactional connections, etc, etc. iSCSI is basically a SAN technology which has many design considerations which will dictate how you carve up available disks to present to the server as a LUN. Considerations such as whether you are mounting a LUN with an application like a database will dictate a certain configuration over if the LUN is just serving up simple file shares. Fault recovery is also a consideration.

The competing technology which some say is a old, dead, and expensive is fiber channel. Fiber channel performs well with SAN storage as fiber channel was optimized for this type of communication. Fiber channel operates on its own infrastructure which requires dedicated HBAs, switches, and fiber. Fiber channel has been around for years and has matured into a fast and very reliable technology. As mentioned before, fiber channel is expensive and does require some one to understand how to set up one. But, it's very fast with lots of bandwidth capacity. Where as the typical iSCSI setup is over a 1 Gb ethernet connection with 1500 byte frames, you have fiber channel operating at current 4 Gb speeds with native 2000 byte frames. 8 Gb fiber channel speeds are starting to become more main stream.

As far as vendors out there, I've laid hands on a Dell Equallogic PS5000 and PS6000 series iSCSI SAN box. The Dell is very easy to setup with a GUI very much like a Linksys router setup. You can get a iSCSI SAN set up in 30 minutes or less with their product. But with all the ease of use mumbo jumbo, there are issues. These may or may not apply to you. So if you want me to elaborate more, I will do so.

With all of the above said, I have a gut feel that a NAS type appliance would be fit more to your requirements.

[IkerSilva]

Thanks! NAS? I think I need more thin management.

[zx10guy]

I don't know what you mean by "more thin management."

[JohnWill]

A NAS is about as "thin" as management gets.

[zx10guy]

Tell me about it. I'm in the process of trying to convince a few people in the office to step into a SAN unit which can also serve duty as a NAS. We've been having tons of issues with having a fileserver with SAN attached storage. It's just one big headache when we have to deal with OS related issues in addition to the additional O&M overhead. It makes life so much easier when we can put in a storage unit that hosts can mount directly for CIFS and NFS with the flexibility to also talk over fiber channel and iSCSI. To me eliminating a fileserver is great when a storage unit can serve up shares and do Active Directory authentication and look ups.

[IkerSilva]

"thin management" in this case means at list that using NAS you should connect to your servers separatly, and using iSCSI you can manage all of them in same time. You can separate one LUN`s traffic and access rights, while other two will work as they did.
After some times googling, and getting answer on the other sites I`ve decided to use software. The only thing is left is which developer is more functional and reliable, for reasonable price.

[zx10guy]

You really need to do more research. Your idea of how the various storage technologies is very skewed. When I say NAS type device, I'm not talking about your typical Buffalo, Netgear, etc, etc NAS appliance. The above features I talked about in post #6 are features you will NOT find in a run of the mill NAS. The NAS heads I'm talking about are offerings from companies like EMC and NetApp.

EMC's offering: http://www.emc.com/products/detail/h...ariion-ax4.htm
NetApp's offering: http://www.netapp.com/us/products/st...ech-specs.html

These NAS heads support full Active Directory look ups so security is fully preserved. In addition, you don't have to share out a particular LUN as a CIFS or NFS share. You can have it as a regular LUN which you can directly mount. Because both devices support iSCSI or FC, you can go one step further by limiting access to the LUNs. Per your statement, you can do this via ACLs via iSCSI or with FC you would do it via zone-ing the LUNs and host initiators along with setting up VSANs (Cisco technology.)

I guess in the end, I don't know your actual requirements and if you're going to take something away from this thread, it's the notion that you really have to get a full handle on what your business needs from a storage system. This may seem simple but if you understand the entire scope of what I am talking about you will know that this is not a simple statement.

[IkerSilva]

Actually idea with iSCSI looks better as for me. I found some vendors, that seems to be reliable. Those are Datacore, StarWind and Lefthand? I know that Lefthand is good, but it is too expensive for me now. Have anybody worked with first two?

[IkerSilva]

Thank you folks for all of your responses, but it was easier to me to use StarWin5. BTW all of your suggestions were good, so I think they might be helpfull, for people, who will view this thread.