OpenSolaris

1. Project: COMSTAR: Common Multiprotocol SCSI Target
   1. Announcements
   2. Events
   3. News
   4. Blogs
   5. Discussions
   6. Leaders
   7. Observers
   8. Files
   9. Source Code
   10. COMSTAR and Linux Multipathing
   11. Demos and Videos
   12. Documentation
       1. COMSTAR Admin Guide
       2. Specs and Man Pages
       3. Release Notes
       4. COMSTAR FAQs

OpenSolaris Project: COMSTAR: Common Multiprotocol SCSI Target

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Storage

Introduction to COMSTAR

COMSTAR is a software framework that enables you to turn any OpenSolaris host into a SCSI target that can be accessed over the network by initiator hosts. COMSTAR breaks down the huge task of handling a SCSI target subsystem into independent functional modules. These modules are then glued together by the SCSI Target Mode Framework (STMF).

In following illustration, the OpenSolaris target host is configured as a storage array using COMSTAR. The initiator hosts can be any platform: Solaris 10, Windows, Linux, VMware ESX, etc.

The modules implementing functionality at SCSI level (disk, tape, etc.) do not need to interact directly with the underlying transport. Likewise, the modules implementing the transport protocol (Fibre Channel, iSCSI etc.) are not aware of the SCSI level functionality inherent in the packets they are transporting. The framework compartmentalizes the execution and cleanup of SCSI commands and the associated resources. This simplifies the task of writing SCSI or transport modules.

COMSTAR features include:

• Extensive LUN Masking and mapping functions
• Multipathing across different transport protocols
• Multiple parallel transfers per SCSI command
• Scalable design
• Compatible with generic HBAs

The port providers implement target transports, such as Fibre Channel. The logical unit (LU) providers implement SCSI logical units, such as disk, tape, and the like.

How to Get COMSTAR

COMSTAR is integrated into the latest Solaris Express Community Edition (SXE). You can get the latest SXCE from the OpenSolaris web site downloads page. COMSTAR is available by default after you install the latest SXCE (end user support or higher metacluster).

Related Projects

• iSCSI Extensions for Remote DMA (iSER) will provide iSCSI support for COMSTAR
• Fibre Channel over Ethernet will provide FCoE support under COMSTAR

Announcements

22 Aug 2008	Emulex added support for COMSTAR
15 Apr 2008	COMSTAR packages updated
20 Feb 2008	COMSTAR Update: sbdadm changes, bug fixes
01 Feb 2008	COMSTAR update: SAS target, new features and bug fixes
14 Nov 2007	Packages and source code available

Blogs

danmas - Multipathing for Tape

Jul 2, 6:24 AM

It was a dark and stormy night, the back up windows opened and shut with the regularity of a 90 year old pensioner's clacking of teeth as he snored with the flem filled nervousness of old age and ...

mac - So you want to build a storage server...

Jun 18, 3:17 PM

You have lots of company. Storage Servers have been around since the days when Sun first put NFS on their workstations. Administrators would load up one workstation with disks and share it with the ...

danmas - Fun in the Sun

Jun 17, 8:35 AM

Deirdré Straughan , Community-Monger and Videoblogger Extraordinaire came to work with me about 18 months ago. She now works in a different organization doing fun things that rightly play to her ...

mac - XAM Java Binding Overview

Jun 16, 9:32 AM

This article was originaly posted to the Royal Jelly blog: http://weblogs.java.net/blog/macsun/ The eXtensible Access Method ( XAM ) is new kind of storage interface for storage devices that can ...

Sumit Gupta - COMSTAR + ZFS Demo is now online

Jun 14, 7:05 PM

Here is a demo on how to take a machine running Solaris and convert it into a Fibre Channel Array using COMSTAR and ZFS. The demo covers all the steps starting right after a fresh install of the OS ...