If Oracle's recent Solaris licensing changes have you singing the blues, OpenSolaris might provide you with a fresh tune to whistle while you work. Last week, the Internet was abuzz with the news that Oracle stopped giving away the Solaris operating system and has now limited the free trial period to 90 days. Now, you must purchase a full license to continue to use the software, per this license excerpt:
Please remember, your right to use Solaris acquired as a download is limited to a trial of 90 days, unless you acquire a service contract for the downloaded Software.
If you're an enterprise user, this change might not affect you. The affected population consists of new adopters, some legacy Solaris users, developers and a few rogue users. Even if you aren't in one of these affected groups, why not make the switch to OpenSolaris or at least investigate it further? It has all of the Solaris goodness (ZFS, Zones, SVM, and hypervisor-based virtualization) without the licensing restrictions or price of the commercial Solaris offering.
OpenSolaris has much to offer the casual user, the mobile user and the data center. Exploring its extensive list of enterprise features might convince you to rethink its use in your data center.
ZFS is an advanced filesystem that offers high performance, near-zero administration, file integrity, scalability, reduced costs and backward compatibility. Without going into a lengthy and complicated discussion of storage pools and block allocation algorithms, realize that ZFS's design features have the enterprise server in mind to extract every bit of performance possible from a disk-based system. ZFS is an intelligent filesystem that can actually adapt its read behavior on the fly for complex read patterns. ZFS also provides built-in compression and encryption.
The word virtualization is on everyone's lips these days and with good reason: It saves you money. OpenSolaris shares built-in OS-level virtualization with its commercial counterpart. Solaris Zones or containers, as they're called, provide the best performance of any virtualization scheme available.
To the user, zones appear as stand-alone systems, but they are actually logical segments or partitions that access the running system kernel. Each zone is an independent segment, and it isn't aware of any other zone and therefore is as secure as a stand-alone system. Often, administrators will "jail" certain applications in zones so that, if compromised, the damage to them won't affect other zones or the host system's integrity.
Many commercial ISPs use zones to provide inexpensive virtual systems to their customers. Each customer has full root access to their "system" and can install programs, edit the system configuration and render their zone useless without affecting any other zone. A compromised or destroyed zone takes only a few minutes to restore to an operational state.
Sun Volume Manager
The Sun Volume Manager (SVM) ships with OpenSolaris as a more traditional approach to volume management. If you use ZFS, you wouldn't use SVM since ZFS handles volume management differently. Typically, administrators use SVM and UFS (the older alternative to ZFS) to mirror disks, create software RAID 5 stripes and cluster configurations. Oracle engineers recommend ZFS because of its performance and advanced enterprise features.
Hypervisor-Based Virtualization (LDoms and xVM)
Logical Domains are Oracle's answer to Type 1 hypervisor-based virtualization, also known as bare-metal hypervisor virtualization, on SPARC hardware. LDoms allow shared and partitioned hardware partitioning. Administrators may assign physical I/O devices to specific domains just as they would memory or CPU or allow those devices to be shared among several domains. LDoms work only on SPARC hardware.
For x86-based systems, Oracle offers its xVM hypervisor technology. Based on the Xen project, xVM virtualization provides paravirtualized and fully virtualized guest operating systems. LDoms allow only guests of the paravirtualized type. OpenSolaris runs as a paravirtualized domain on both hypervisors as a control domain.
OpenSolaris has other advanced, enterprise-oriented features, such as its ability to run on 32-bit and 64-bit architecture and on single and multiprocessor systems. It also offers IPv6 networking, complex resource management, advanced security (including role-based access control), a modular kernel, full POSIX compliance and an integrated AMP stack (Apache, MySQL, PHP) for use in operating highly scalable database-backed Web sites.
OpenSolaris is also an open-source technology. It's licensed under the Common Development and Distribution License (CDDL). Like Linux, and other open source projects, OpenSolaris has a global user community dedicated to its continued development. If you think you'd like to dance to a new unrestricted tune, OpenSolaris is still free and ready to serve.
Ken Hess is a freelance writer who writes on a variety of open source topics including Linux, databases, and virtualization. He is also the coauthor of Practical Virtualization Solutions, which is scheduled for publication in October 2009. You may reach him through his web site at http://www.kenhess.com.