Promise Technology Version 4.4 user manual Appendix a RAID Concepts

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Appendix A: RAID Concepts

RAID is an acronym that stands for Redundant Array of Independent Disks. It is divided into different numbered Levels. The numbers of these Levels do not mean that one Level is higher or better than another. Each Level has its own advantages and shortcomings.

PAM allows you to select the RAID Level when you create an Array. The available RAID Level selection depends on which Promise product you have and the number of disk drives available. The table below lists the options.

	RAID Level	Performance	Fault	Capacity	No. of
	RAID Level	Performance	Tolerance	Capacity	Drives
			Tolerance		Drives

	RAID 0	Highest	No	No. Drives x	2 to 4
	(Striping)	Highest	No	Smallest Size	2 to 4
	(Striping)			Smallest Size

	RAID 1	Normal	Yes	Smallest Size	2
	(Mirroring)	Normal	Yes	Drive	2
	(Mirroring)			Drive

	RAID 0+1	High	Yes	2X Smallest Size	4
	(Stripe/Mirror)	High	Yes	Drive	4
	(Stripe/Mirror)			Drive

	RAID 5	High	Yes	No. Drives -1	3 or 4
	(Distributed Parity)	High	Yes	No. Drives -1	3 or 4
	(Distributed Parity)

	JBOD
	(Just a Bunch of	Normal	No	Sum of all drives	1 to 4
	Disks)

Figure 82. RAID Levels obtainable with FastTrak SX4000 series and S150 SX4.

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Contents FastTrak S150 SX4 and SX4000 series Copyright TrademarksImportant data protection information Contents Promise Array Management PAM Components IntroductionHow They Work Together LAN and Internet connections PAM Installation OptionsCompany LAN without a File Server PCs with Internal RAID Promise Array Management Installation Installation LocationsMonitoring Utility Networked RAID has many installation options Operating System Support Message ServerMessage Agent Pre-Installation Procedure PAM InstallationNetwork Requirements PAM Setup Opening Screen Setup Type dialog box Add User Account dialog box Install Complete dialog box Launch PAM Initial SetupLocal PAM Log-out Local PAM Log-inCreate a New Server Remote PAM Log-inDisconnect from a Message Server Remote PAM Log-outLogout of RAID PC Remote PAM Future Log-insPAM Monitor window has three views PAM User InterfaceUser Information View Create a New UserCreate an Array Create Array Settings New Array CRAM-MD5 Setup Email Alert NotificationEmail Sender and Recipients Add a User to the Recipient ListSpecify Alert Notification Events Event Alert Setting boxInformation Events PAM User Interface Local PAM Tree ViewAn example of a RAID system in Tree View on Remote PAM Remote PAMObject View Tree View and Component Specific MenusStatus Bar Information ViewMy Console Menu Pulldown MenusDynamic Menus Main MenuMaintenance Menu RAID Machine MenuRAID System Menu Connection Menu Remote PAM only View MenuHelp Menu Preference MenuToolbar ToolbarRAID Machine Icon Popup MenusMy Console Icon Message Server IconDisk Icon RAID System IconController Icon Channel IconArray Icon User Management IconUser Icon Promise Array Management RAID Monitoring Maintenance with PAM Local PAM Log-inLog-out Remote PAM Create a RAID Server Delete a RAID Server Disconnect from a Message ServerLogout of RAID PC Future Log-ins Message Server IP Address Change Create a New User Manage UsersChange Password Delete a UserChange User Rights Alert Notification Add a User to the Recipient List Current Recipients window Delete a User from the Recipient ListSpecify Alert Notification Events Information Events Controller View Event LogRead Bad Sector Table System Information Controller OptionsRebuild Setting Controller CacheDisk Parameters Maintenance Error Handling Inconsistency Error HandlingPCI Bus Utilization Create an Array ArraysCreate Array Settings New Array Scheduled Synchronization Synchronize an ArrayStart Synchronization On Demand SynchronizationStop, Pause, Continue Synchronization SettingsExpansion Expand / Convert an ArraySelect a disk drive to add to the array Verify the Array name and click Finish From Comments ConversionStart Conversion Select the new RAID Level Conversion progress Array Critical RAID Monitoring and Maintenance Automatic Rebuild Rebuild an ArrayStart Rebuild Wizard Manual RebuildRebuild Wizard Confirmation window Rebuild Settings in Information View Rebuild SettingsError Handling Delete Array Array OfflinePromise Array Management Appendix a RAID Concepts RAID 0 writes data to both drives at the same time Striping RAIDData Mirror Disk Drives Mirroring RAIDStriping / Mirroring RAID 0+1 About Dual Data Redundancy RAID 5 Stripes all Drives with Data and Parity Information Block and Parity Striping RAIDJbod manages drives Individually, unlike RAID Jbod Single DrivePromise Array Management Right-click on the My Computer icon Appendix B Partition and FormatDisk Management Window and Disk Wizard New Partition Wizard Newly formatted array as it appears under Disk Management IP Address Appendix C Networking IssuesDhcp enabled. . . . . . . . Yes Dhcp IssuesAppendix D Technical Support Technical Support ServicesPacific Rim Sales Office