LVS 4500 RAID Storage System

Amdahl means business with the LVS 4500 RAID Storage System. Designed to be the top of the line, this system comes with features such as support, performance, high availability, flexibility, and flexible management abilities.

When the going gets tough as numerous users access huge databases, the LVS 4500 RAID storage system gets going. The system's hard disks connect to disk interface processors, which communicate over five internal buses to the Logical Storage Modules (LSMs). Each LSM has 256MB of high-speed cache memory and can achieve throughput rates of up to 80Mbps. Other technologies that let the system effectively perform during critical times include differential SCSI-3 technology, fibre channel connectivity, intelligent caching, and hardware RAID parity calculations.

Amdahl designed the LVS 4500 not only for performance but also for protection. This storage system protects your data, from the host system all the way to the hard disks. You can configure this system to use RAID levels 0, 1, 3, 5, or 1+0 in any combination to store the data. You can even configure a global hot-spare hard disk to automatically replace a failed disk, letting you continue operations without interruption.

Amdahl has protection mechanisms for any contingency. To prevent data loss in a power failure, the LSMs have 72-hour battery backup. To prevent data loss in the event of an LSM component failure, each cache automatically mirrors to another cache on a different Availability Manager controller over a high-speed channel. In the event of a problem with a total LSM failure, including the cable to the host system, the LVS 4500 uses Amdahl's LifeKeeper monitoring software to redirect the data I/O to another LSM. (Amdahl includes this software with the system.) All active components are redundant and hot swappable, so you can replace them without affecting operations.

Upgradeable to Meet Changing Needs
The LVS 4500 is an expandable system. Each LVS 4500 enclosure can house up to 20 hard disks, including the latest 9.1GB Seagate hard disks, to give you 182GB of online storage. If you need more storage, you can add a Storage Expansion Module (SEM), which gives you room for 10 more disks and 273GB of online storage. If you have extremely large databases that must be online, you can hook up a maximum of three systems in a data center cabinet for a total of 90 online hard disks with 819GB of storage. You can buy the LVS 4500 with as much as 256MB of cache memory per LSM, giving you up to 128MB of mirrored cache memory or the full 256MB cache if you turn the mirroring off. Because Amdahl supports this system on multiple host platforms, you can even change platforms but keep your storage system.

To increase LVS 4500's performance, you can upgrade to solid-state disks. SSDs take the mechanical aspects of retrieving data out of the picture by using computer memory modules in place of a physical hard disk. Thus, they increase the data transfer rates from slow mechanical speeds to much faster electrical speeds. Although SSDs increase performance substantially, they are more expensive than hard disks.

You can also upgrade the LSMs to support Fibre Channel technology. Currently, the system supports only point-to-point links. Amdahl will support arbitrated loop and fabric switch links in the near future. With Fibre Channel, the LVS 4500 can achieve data rates of 200Mbps between the storage system and the host.

The LVS 4500 comes with two flexible, easy-to-use management software packages: A+LVS and A+LVS/NetDirect. A+LVS lets you configure the storage system, check its status, and adjust recovery options. A+LVS/NetDirect lets you configure the storage system from anywhere in your network.

Check It Out
The system I reviewed came with twenty 9.1GB Seagate hard disks and two Availability Manager controllers with 320MB of memory per controller. Amdahl originally configured this system for use in a dual-system cluster. I reconfigured the LVS 4500 for use in a single-host system and used an Amdahl EnVista Server Model FS and two Adaptec 2944 Ultra SCSI controllers to test it.

Installing the LVS 4500 was fairly easy. I encountered some initial installation problems, but I quickly resolved them by talking with Amdahl's support personnel. I began by installing the two Adaptec controller cards, connecting the cards to the LVS 4500 with long SCSI differential cables, and turning the system on. I then booted the server and installed the A+LVS software, which installed a system driver, the Disk Array Monitor NT service, and the RAID Manager software. Once again, I had to reboot the system because I had installed a system driver and NT service.

When the system came back up, I selected the configuration option in RAID Manager and reconfigured the system the way I wanted it. I made one disk a hot-global spare, selected the number of disks I wanted to use, and set up a RAID 5 configuration. The system then automatically selected the best configuration for this setup. (If I wanted, I could have overridden this setup and manually selected disks and buses.) Next, I used the NT Disk Administrator to partition and format the array. Finally, I installed SQL Server onto the array.

The storage system worked as intended. The software is easy to use and gives you a lot of control over the system.

Overall, this system and with the professionalism of Amdahl support personnel impressed me. If you need a disk subsystem that is fast, fault-tolerant, upgradeable, and easy to manage, the LVS 4500 is worth checking out.