LVS 4500 RAID Storage System

Store and retrieve data on multiple host platforms

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 LVS4500 RAID storage system gets going. The system's hard disks connect to diskinterface processors, which communicate over five internal buses to the LogicalStorage Modules (LSMs). Each LSM has 256MB of high-speed cache memory and canachieve throughput rates of up to 80Mbps. Other technologies that let the systemeffectively perform during critical times include differential SCSI-3technology, fibre channel connectivity, intelligent caching, and hardware RAIDparity calculations.

Amdahl designed the LVS 4500 not only for performance but also forprotection. This storage system protects your data, from the host system allthe way to the hard disks. You can configure this system to use RAIDlevels 0, 1, 3, 5, or 1+0 in any combination to store the data. You can evenconfigure 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 lossin a power failure, the LSMs have 72-hour battery backup. To prevent data lossin the event of an LSM component failure, each cache automatically mirrors toanother cache on a different Availability Manager controller over a high-speedchannel. In the event of a problem with a total LSM failure, including the cableto the host system, the LVS 4500 uses Amdahl's LifeKeeper monitoring software toredirect the data I/O to another LSM. (Amdahl includes this software with thesystem.) All active components are redundant and hot swappable, so you canreplace them without affecting operations.

Upgradeable to Meet Changing Needs
The LVS 4500 is an expandable system. Each LVS 4500 enclosure can house upto 20 hard disks, including the latest 9.1GB Seagate hard disks, to give you182GB of online storage. If you need more storage, you can add a StorageExpansion Module (SEM), which gives you room for 10 more disks and 273GB ofonline storage. If you have extremely large databases that must be online, youcan hook up a maximum of three systems in a data center cabinet for a total of90 online hard disks with 819GB of storage. You can buy the LVS 4500 with asmuch as 256MB of cache memory per LSM, giving you up to 128MB of mirrored cachememory or the full 256MB cache if you turn the mirroring off. Because Amdahlsupports this system on multiple host platforms, you can even change platformsbut 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 usingcomputer memory modules in place of a physical hard disk. Thus, they increasethe data transfer rates from slow mechanical speeds to much faster electricalspeeds. Although SSDs increase performance substantially, they are moreexpensive 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 supportarbitrated 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 andthe host.

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

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

Installing the LVS 4500 was fairly easy. I encountered some initialinstallation problems, but I quickly resolved them by talking with Amdahl'ssupport personnel. I began by installing the two Adaptec controller cards,connecting the cards to the LVS 4500 with long SCSI differential cables, andturning the system on. I then booted the server and installed the A+LVSsoftware, 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 Ihad installed a system driver and NT service.

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

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

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