How does hard disk drive configuration impact Scala performance and stability?

Isn't it amazing how the fastest of computer workstations can be made to appear slow through the inappropriate configuration of its hard disk drive storage system? While computers have increased in performance by a factor of 2000 in the past twenty years and hard disk drives have increased in capacity by at least a factor of 10,000, the "average seek time" of hard disk drives has really only improved by a factor of 10. It is this "average seek time", the speed at which a hard disk drive get actually get to the data on a disk platter, that is one of the major limitations on the performance of an IC Player. When planning the layout of files and partitions on are hard disk the goal is to minimize the overall time the drive will spend getting to the data it needs to retrieve.

The following techniques can prove useful:

• In a single logical volume disk system, (such as ONE Hard Disk Drive or ONE RAID-1 or RAID- 5 HD set), separate files that change frequently from files at almost never change. The means that if a given player is going to receive frequent updates of artwork; place these frequently changing files on a disk partition of their own.
• Place the files that change the most near, (as is practical), to the middle of the disk drive.
• Separate very large files from very small files. In order to prevent excessive file fragmentation in a system that is designed for long term operation; place small files that change frequently, (backgrounds, clips, anim-GIF's, fonts, scripts), in a partition that is separate from large files that change frequently, (MPEG movie streams, large AVI's, audio files that are many seconds or minutes long, etc.)

A single disk drive Windows2000 or XP Scala player that is intended for long term IC playback - a Player that might receive 10-20 MB of script content updates per day, around 200 MB of new artwork - plus maybe one or two 400 MB MPEG files per week. This would make for a system with an "active" script size or around 1500MB or so. [with the assumption that a significant portion of its 'standard' artwork will reside on the hard disk drive from its initial configuration and not be removed] A 20 GB drive is partitioned into four slices: a 2000 MB FAT32 partition for a "Recovery" minimal Windows 2000 installation with all OS-related installation files and Device Drivers, Service Packs, Patches and key utilities; a 4000 MB NTFS partition with the full "Root" Operating System installation; a 2000 MB NTFS "Swap" partition for a 2xPhysical- Memory-in-MB sized Permanent 'swap file', (PAGEFILE.SYS), for virtual memory paging and of the rest as free space for the System '%TMP%', '%TEMP%', and '%SPOOL%' directories for temporary files of various types; and a ~12 GB NTFS "Scala_DATA" partition for the "Documents and Settings" directory tree, a FTProot directory tree for NetManager3 file transfers, and the Scala Program directory tree.

 
If this player were intended to regularly receive large MPEG-2 files--say a new 30 minute video clip every day--it might make sense to either have another "Large File Partition" near the middle of the hard disk drive between the "Swap" and "Scala_DATA" partitions with a "JUNCTION POINT" to a directory under FTProot on the Scala_Data partition. [Or, even better, to have a totally separate hard disk drive with LARGE, 32KB, NTFS Clusters so that the depositing and playback of these massive files have a minimal impact on the operations of the rest of the system.]

For a high performance/high capacity Player system two obvious permutations would be:

• Use a "Four Disk EIDE RAID-5 Controller", such as the Adaptec AHA2400A set up four EIDE devices as either a "RAID-0+1 Strip/Mirror Set" or a single "RAID-5 Set" and distribute your partitions on the resulting single logical device.

• Make the "Recovery" volume a RAID-1 set of its own.

• Have the "Root" OS and "Swap" partitions be located on a RAID-1 sets of their own.

• Have the "Scala_DATA" partition be on a RAID-5 SCSI volume set of its own comprised of THREE or more physical devices.

Note: this form of "ultimate performance and security" would require a _minimum_ of SEVEN physical hard disk drives to host the four partitions on THREE logical volume sets!

Large Capacity Storage for Players

A recommended form of low cost high-availability LARGE CAPACITY storage is in the form of an EXTERNAL "Network Attached Storage" device. Both Quantum and Maxtor have 1 UNIT (high) external rack mount NAS devices with JABOD/RAID-0 capacities from 40 GB to 960

GB--20 to 480 GB in RAID-1 or RAID-5 configurations. [in this use the player should be equipped with a PCI NIC that has DUAL 100 Mbps Ethernet connectors--one for the general LAN/external connectivity; one for a 200 Mbps "FULL-Duplex 'X-Over'" connection to the external NAS device.

• Examples: Maxtor MaxAttach and "SnapServer" products http://www.maxtor.com

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