Data Centers

Getting to know the IDE RAID controller

If data warehousing is part of your department?s duties, you?ll be glad to know that RAID can now be used with the less expensive IDE drives. Troy Thompson outlines how to use the SuperTrak100 IDE RAID controller card.

If you need to warehouse large amounts of data but have found the SCSI route to be cost prohibitive, there is now a cheaper way. In this Daily Drill Down, I’ll look at the Promise IDE RAID controller card, SuperTrak100. This card will allow you to set up a mass storage device using IDE drives. This solution to RAID is less expensive than using a SCSI controller and SCSI drives. The SuperTrak100 controller card is compatible with Windows NT or Windows 2000.

Features of SuperTrak100
The features of the SuperTrak100 include support for standard IDE drives such as Ultra ATA, DM A, and EIDE, as well as Ultra ATA/100, Ultra ATA/33/66, EIDE, and Fast ATA-2 (UDMA 5/4/3/2/1/0, PIO 5/4/3/2/1/0, and DMA 2/1/0, respectively). It also supports redundant arrays of independent disks (RAID) and will perform automatic background rebuilds for mirrored arrays. It has a complete read/write cache management and onboard controller card memory that enhances cache size. It also supports hot-swappable hard drives and drive fault detection. It can be installed on a Windows NT or Windows 2000 server. These features will be discussed in more detail later in this Daily Drill Down.

Data warehousing
Data warehousing refers to using a mass storage device, such as a server, to store large amounts of data. These devices can be used to archive data, to replace slow CD towers, or even to back up your system instead of using tape. With the cost of hard disks falling, this type of functionality is not a luxury anymore. Since the SuperTrak100 will support up to six drives, and you can easily find affordable 80-GB drives, you can conceivably have œ terabyte of storage on your network for a cost that is 70 percent less than using SCSI.

RAID explained
In a standard PC, each hard drive is seen as an independent disk designated by a letter, such as C, D, E, etc. In a RAID system, multiple hard drives are placed into one or more arrays of disks. Each array is seen as an independent disk, though that array may include upwards of two, three, four, or more drives. There are several types of RAID configurations.

Disk striping without parity (RAID level 0) provides no data redundancy and is not fault-tolerant. It requires a minimum of two disks and can be formatted with FAT or NTFS partitions. It offers the highest level of read and write performance of any available disk management strategy by allowing concurrent requests to be processed on all drives simultaneously.

Disk mirroring (RAID level 1) supports only two hard drives. Mirror sets are the only form of fault tolerance that can include system and boot partitions. RAID 1 has both drives running off the same controller. Disk duplexing is the same as mirroring, except it uses two disk controllers instead of one (a hardware enhancement vs. a software enhancement). Disk mirroring is the least cost-effective disk management strategy because you lose half of your disk capacity.

Disk striping with parity (RAID level 5) provides fault tolerance. RAID 5 uses a mathematical expression that compares data from two drives and calculates a third piece of data called parity. Should one of the drives fail, parity data can be used to rebuild the failed data. It requires a minimum of three physical disks and can have as many as 32 disks. All partitions in a stripe set are the same size. If you select free disk areas of different sizes when you create a stripe set, no stripe will be larger than the smallest free disk area. For instance, if you have 200 MB, 400 MB, 600 MB, and 800 MB free on each of four drives, only 200 MB is used on each drive. The entire stripe set will be 800 MB in size. The space equivalent to one partition is used for parity information. So, in this case, one fourth is used for storing parity information (200 MB), and only 600 MB of data can be stored on the stripe set. Regardless of how many disks are used in a stripe set with parity, data is recoverable only if no more than one disk is lost. If two or more disks are lost, the data is unrecoverable.

Choosing a server
If you want to use the SuperTrak100 IDE with six drives, you will have to plan on getting a large case. You will probably also want to add a floppy and CD-ROM drive. It is a good idea to install the operating system on a drive that is not part of the RAID, so that will add one more drive to the mix. Finding a case that will support seven hard drives, a floppy drive, and a CD-ROM drive is not difficult, but it is also not the norm. Having adequate ventilation and power are other considerations. You may be able to resort to using an old CD-tower case if you have one available. Otherwise, you can purchase a multislot case with Pentium processor, 512 MB of RAM, NIC card, CD-ROM, and floppy for less than $2,000.

Hot swap
SuperTrak100 also offers the ability to hot swap failed drives when used with the optional SuperSwap hot swap enclosure. These enclosures cost about an extra $100 per disk. The disk itself plugs in to the enclosure, and then you mount the enclosure into the server case. A handle on the front of the enclosure allows you to quickly and easily remove the entire drive. This provides continuous operation without powering down a system in the event of a failed drive. The enclosure fully protects drives and PC electronics when drives are removed and/or replaced in a running system.

In addition, SuperTrak100 manages and monitors the arrayed drives and enclosures in two ways. First, SuperTrak100/SuperSwap displays drive status (failed, rebuilding, normal) and power/activity status. Second, SuperTrak100's advanced array management utility monitors the status of the enclosure for temperature, fan status, and voltage regulation.

Promise recommends using identical drive sizes for best performance and compatibility.

SuperTrak100 controller
To use the SuperTrak100 IDE RAID controller, your server must have one bus mastering PCI slot (PCI v.2.1 compliant). It also requires 8 MB EDO 72-pin SIMM for cache RAM (units may ship with 16 MB). You must have one to six Ultra ATA/100, Ultra ATA/33/66, or EIDE hard drive(s) for dedicated use in the RAID array and Windows NT 4.0/2000 (or later) on server stations; Windows NT 4.0/2000 or Windows 95 (or later) on remote monitoring stations. SuperTrak100 was designed to specifically support Windows NT 4.0/2000 and later; you may employ other operating systems to access many of its operational features. Windows NT 4.0/2000 is recommended to take full advantage of all the features of the SuperTrak100 package. The SuperTrak100 Message Server and Message Agent are NT/2000 services and will only function on an NT/2000 system.

You should record your current CMOS (system setup) settings before making any changes. This preventative measure is aimed at protecting such information from loss, which may happen unpredictably and/or periodically during any hardware installation.

The package for the SuperTrak100 will contain the controller card, user’s manual, drivers, utilities disks, and six 18” Ultra ATA/100 80-wire/40pin hard drive cables.

At least one drive is cabled and attached to the controller. The SuperTrak100 controller card is fully inserted into a bus mastering PCI slot and mounted with a bracket screw.

A minimum of 8 MB of EDO RAM is inserted into the SIMM slot on the controller card. A 3V (CR2032 or compatible) battery is installed correctly on the controller card and the protective label removed. The card is quite long (14 inches), so you will have to make sure there is adequate space in your case for it.

The Promise SuperTrak100 BIOS is loaded during the boot process. You can press [Ctrl]F to set up the disk array. You can auto-configure the drives using this utility; however, you will still have to install the Windows 2000 drivers and configure it in Disk Management.

Using SuperTrak100 with Windows 2000
New Windows 2000 Installation
If you are installing Windows 2000, you can load the device drivers for the SuperTrak100 by pressing [F6] when prompted with the message Press F6 If You Need To Install Third Party SCSI Or RAID Driver. When the Windows 2000 Setup window is displayed, press S to Specify an Additional Device. Insert the Promise Technology  driver disk into drive A: and press [Enter]. Choose Win2000 Promise SuperTrak66/100 Controller from the list that appears on screen, and then press [Enter]. The Windows 2000 Setup screen will display the message Setup Will Load Support For The Following Mass Storage Devices: The list will include Win2000 Promise SuperTrak66/100 IDE RAID Controller. Continue the installation of Windows 2000.

Existing Windows 2000
After installing the SuperTrak100 card and rebooting your system, Windows 2000 setup will show a New Hardware Found dialog box. In the dialog box, you must choose the Driver From Disk Provided By Hardware Manufacturer button. Check Search For A Suitable Driver For My Device (Recommended) and then click Next. The next window will be Locate Driver Files. Uncheck Floppy Disk Drives, check Specify A Location, and then click Next. Insert the SuperTrak100 driver disk in the A: drive and type A:\WIN2000 in the text box. Press [Enter] to continue. A message saying Windows2000 Promise SuperTrak66/100 IDE RAID Controller should appear. Click the Next button to continue and choose Yes when presented with the Digital Signature Not Found dialog box.

To complete the setup, click the Finish button and reboot the system. Once the computer has rebooted, you can confirm the installation by opening Control Panel and choosing the System applet. Under the Hardware tab, click Device Manager and expand the SCSI And RAID Controllers entry by clicking on the plus sign. When the plus sign expands the contents, you will see the Win2000 Promise SuperTrak66/100 IDE RAID Controller listed.

Once the driver is installed for Windows 2000, you will insert the Utility Disk 1 and run setup to install SuperCheck. SuperCheck has three modules: Console, Message Server, and Message Agent. These modules use TCP/IP connections to communicate with one another, allowing communication across a network.

This allows system administrators to monitor and rebuild the SuperTrak RAID system from a local console or a remote workstation over the Internet, with controlled user group administration, secure data encryption, and flexible control options.

Windows 95/98 and its successors employ the WIN32 interface required by the SuperCheck monitoring utility software. This means that SuperCheck may be implemented on a Windows 95/98 station or remote terminal to connect to Message Servers that exist on a network. Using the SuperTrak100 int 13h BIOS interface, it is possible to access the drive data on an array to partition, format, copy files, etc., using DOS 7 or later. DOS versions earlier than 7.0 have an 8.4-GB drive size limit, which cannot be changed. Other operating systems are not supported at this time.

If you have a firewall installed, you will have to open a communications port for the IP address on which the Message Server resides in order to perform a remote connection. The port to be opened is port 711 (decimal) on the IP address. This will allow the SuperCheck software to initiate a TCP/IP connection from the remote location through the firewall port 711 to the Message Server located at the destination IP.

The SuperTrak100 was a breeze to install and configure. When used with its companion software management suite, SuperTrak100 offers a secure and expandable RAID environment that is cost-effective.

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