iSCSI: Software or Hardware?

Question

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?

Answer 1

1. Why do you think you need iSCSI?
2. There's no description of the use case at all. If you elaborate, people will have an easier time suggesting a solution
3. In general terms, if you can afford a proper storage box, it's always better than a self made custom storage, but the cost might make a serious difference, so you need to count your RoI.
4. Storage is not only about the SAN link type, but more importantly - the backplane BW, spindle counts, infrastructure redundancy and quite a few other factors. It all depends on the usage and requirements.

I have all of my iSCSI production running on dedicated hardware - Netapp filers, EMC and Dell MD3000i. For testing a RHEL box with tgtd is generally enough.

Answer 2

Dyasny asks some good questions. I have a few more.

First of all, what O/S are you running? Third party vendors are notorious for not knowing anything about Linux or Solaris, for example.

Next, what is your Ethernet infrastructure like? Is it banks of managed layer 3 switches with VLANS, redundant trunks, spanning tree, and EtherChannel? Or is it a few old NetGear/DLink 10/100 switches strung together by their gigabit uplinks?

In order to get good performance and reliability from iSCSI, you need end-to-end Gigabit, EtherChannel, and either VLANs or a physically separate network. If you are expecting to just plug all the clients into a cheap gigabit SoHo switch, you have more problems and expenses ahead of you then you realize.

For your first foray into iSCSI, I suggest getting everything from your server vendor. Then you have "one throat to choke" until you get everything right, and learn how it all works.

Answer 3

Or you can try something free-ware for learning iSCSI. I would offer you to try FalconStor(use it on ESXi), openfiler(Linux) or StarWind Free(Windows). FalconStor is for VTL. I`m using StarWind now.

Answer 4

As others have pointed out, the concept of separating Software and Hardware iSCSI SAN solutions is puzzling. Could you clarify a little more concerning what it is that you meant by that? At their heart, virtually all SANs/NASs are differentiated by their management software, the stuff that makes the snapshots, manages the LUNs, tiers the data etc. and etc. (Yes, there are hardware differentiations of course, but really, IMO, the truly unique differentiation is in the software).

IMO, you have two possibilities staring at you:

• Unified Storage
• Dedicated SAN storage

Let's look into them briefly:

Unified Storage

Brings SAN and NAS features into one management interface and one piece of hardware. Great for small/medium businesses that don't need the speed of dedicated SAN equipment and want the flexibility to be able to manage all their networked storage from one place.

As far as Unified Storage goes, you have to possibilities. First, you can get software that can be installed on virtually any piece of hardware and go from there. (That might have been what you meant by "software solution?") The second option is to get dedicated a solutoin that has inseparable hardware/softwar.

Some examples of solutions that can be purchased or used virtually independent of the hardware that it is installed on inlcude the open-source OpenFiler and FreeNAS and the proprietary Nexenta (built on OpenSolaris). That reminds me, OpenSolaris itself can provision NFS share as well as iSCSI targets.

Some examples of hardware/software unified storage solutions include Reldata and BlueArc. The big boys do it too, like NetApp and HP.

Dedicated SAN

Dedicated SAN systems will most likely be on a dedicated network that is not disturbed by direct user traffic and will have management software that is tailored to SAN needs. You have many options in this field, some of which include Compellant, Xiotech and 3Par (I deliberately ignored some of the larger players since they're 1. Overpriced for SMBs and 2. OverHyped)

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Of course, you could get unified storage software like Nexenta or OpenFiler, drop it on a nice piece of hardware and never use the NAS features but only utilize it's iSCSI features. That's up to you. I would counsel that in some cases, SAN solutions would give you better management and flexibility over "Jack-of-all-Trades" solutions, however only your carefully crafted Specifications Sheet compared to the product's features will be able to determine that.

Purely my opinion based on no specifications from you: I would trust shared storage more to a dedicated SAN solution than a unified storage product. Specifically I'd go with Compellant or 3Par for their reputed ease of management, cutting edge features and lower prices than NetApp/EMC.

Answer 5

For business iSCSI solutions, you could do worse than going for Dell iSCSI SAN solutions.

Quite affordably priced too, and most importantly, great Dell business support and a trusted business brand.

Answer 6

I cant mark answer as correct, so I want to tell al lof you that it is Araz`s answear. I'm using StarWind now.

Answer 7

It depends to the budget. If its not big, than itll be better to use reliable software solution, than hardware. In this case you have no need to buy additional hardware. The question which vendor can offer better product.

Answer 8

Who makes your server hardware? I found tech support works best for me when it all comes from the same vendor.

Besides that, I've found that extended warranty & tech support contracts are much cheaper from Dell and HP then from small third party vendors who think they own the iSCSI name.

Answer 9

There's no such thing as a "hardware iSCSI solution". In maybe 90% of the cases if you'd open "hardware iSCSI" box you'd find cheap x86 hardware and stripped down Linux to do iSCSI job. In the other 10% of the cases x86 hardware could be swapped in favor of ARM or MIPS low-gigahertz cores but it's still Linux... And it does not matter how they call it - StorageOS or HALO, it's just plain Linux re-named :) So, in a nutshell: you can grab up to date PC hardware, install free Linux target and have a solution running circles areound ANY pseudo-hardware iSCSI box. If you don't want to mess with a Linux thing - worth giving a try to the Windows-based targets. Like StarWind. Or DataCore (if you're on expensive side).

-ichiro

Answer 10

If your budget can afford it, I would go with Dell EquaLogic series.

They are expensive but they are the best on the market and comes fully loaded with stuff like offsite byte level replication.