What is the difference between InfiniBand, SAS and iSCSI and where does each technology fit?

InfiniBand is an interface; just like Fibre Channel (FC) or Ethernet. As an interface, InfiniBand carries different

Requires Free Membership to View

protocols. For example, the SCSI command set can run on InfiniBand but the SCSI command set can also run on top of FC. iSCSI-carries the SCSI command set on IP (Ethernet). By comparison, SAS is an interface for attaching disk drives to servers, storage arrays to servers and to attach disk drives within storage arrays.

SAN information

What is iSCSI? Read a definition from WhatIs.com.

Why don't we have clustered FC block storage?

Fibre Channel Arbitrated Loop or switched disk?

Hard zoning vs. soft zoning

You can have a server with an InfiniBand host channel adapter (HCA) that attaches to an InfiniBand disk array. That InfiniBand connection can run SCSI, iSCSI or some other protocol. In turn, this can be talking to an array that has SAS disk drives attached to it. In a small environment, you might use SAS to attach a local SAS drive in a 1U blade server. Alternately, you might have SAS in a disk array coexisting with SATA drives. Otherwise, you might have network storage with iSCSI to access a disk array with SAS disk drives in it.

These technologies all work together in a complementary fashion even though they are typically positioned against each other. For example, you might hear an argument for InfiniBand vs. iSCSI the same way that FC is normally positioned against iSCSI -- they are apples and oranges. InfiniBand is an interface, so it should be compared to FC or Ethernet. Then, compare your protocols, such as iSCSI vs. "SCSI on FC" or "SCSI on InfiniBand." InfiniBand, SAS, iSCSI are all very much complementary.

Listen to the SAN FAQ audiocast here.

Go back to the beginning of the Storage Area Network FAQ Guide.


This was first published in January 2007

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to: