Survey of Sun Storage Subsystems

Sun provides a range of storage options ranging from local SCSI disks to the highly resilient and performant Sun StorEdge 9900 series. Given such a large range, decisions have to be made as to which systems are the most appropriate to deploy for the Sun ONE Directory Server 5.2 software. Please note, however, that networkattached storage is not a supported configuration for the Sun ONE Directory Server software and should not be used. In addition to providing relatively poor performance compared to the other possibilities, network file systems like NFS and AFS also do not support the kinds of locking required by the directory server database, so when using them you run the risk of corrupting the directory server database.

The Sun StorEdge T3b storage array is widely deployed and is seen as the mainstay for the Sun ONE Directory Server 5.2 software to achieve maximum performance. For this reason, a large portion of this section is devoted to its configuration.

Local SCSI Disks, Internal FC-AL Disks, High-End Storage

As an example, Sun has a broad family of Sun StorEdge Solutions, including the Sun StorEdge 3310 SCSI array which is the only SCSI array; the Sun StorEdge D1000 array, which is a host-based software RAID device; the Sun StorEdge A1000 array, which is a hardware RAID device; and the Sun StorEdge D2 Array, which is ideal in a workgroup array.

Even though the Sun StorEdge A1000 array is still available, it should be disregarded and probably not used with the Sun ONE Directory Server 5.2 software because it is probably coming to the end of its life, and has relatively slow SCSI disks and a small cache size of only 64 Kbytes.

For lower-end systems such as the Sun Fire E280R and Sun Fire v880 systems, it is feasible to use these disk subsystems in conjunction with the Sun ONE Directory Server 5.2, in particular when deploying in an enterprise environment. In general, using internal SCSI disks is possible with systems such as the Sun Fire E280R and Sun Fire v880 systems with disk subsystems such as the Sun StorEdge 3310 array and above, as they do warrant a disk array with read/write caching and hardware RAID controllers.

Storage Arrays with Cache

Sun offers a wide range of storage arrays which includes the Sun StorEdge 3310 array and above that have cache and hardware RAID controllers. In all cases, they can be configured with dual controllers and mirrored storage.

The latest incarnation of the Sun StorEdge T3 array is the T3b, which has a 100 Mbyte/sec fibre controller, 1-Gbyte cache, and fast fibre-channel arbitrated loop (FCAL) disks. Management of hardware RAID within the array is accomplished using the simple onboard UNIX-like interface to its operating system (for example, you can use the telnet command to communicate with the array and configure it through a set of simple commands). Scalability, which equates to more disk space and more controllers for more I/O operations and throughput, is achieved by adding more Sun StorEdge T3b arrays. There are no licensing issues or additional cabinets to purchase, so the Sun StorEdge T3b array is a relatively inexpensive path to follow. As needs grow, you simply add a new array. The Sun StorEdge T3b array is a mid-priced storage device, and is therefore a good price/performance fit for machines with 2-24 processors.

Note

The Sun StorEdge T3b arrays can be clustered, but doing so requires additional infrastructure such as fiber switches or hubs.

High-End Storage Subsystems

The high-end storage subsystems currently available include all of the Sun StorEdge 9900 range of products. These provide very high levels of availability, using software to predict and automatically swap and replace disks that are likely to fail. High levels of performance are provided by virtue of large caches and multiple paths to fast disks. Furthermore, these subsystems readily support multi-hosting, which is an advantage in a clustered Sun ONE Directory Server 5.2 environment. The disadvantages of the Sun StorEdge 9900 range of products are the price and the initial complexity in setup and implementation.