User Manual

549
Product Manual Technology Background
technology BAckgRounD
This chapter covers the following topics:
• “DiskArrays”(seebelow)
• “LogicalDrives”onpage551
• “SpareDrives”onpage580
• “RAIDControllers”onpage587
• “iSCSIManagement”onpage593
• “InternetProtocols”onpage601
disk arrays
Disk array technology includes:
• “MediaPatrol”
• “PDM”
MediA PAtrOl
Media Patrol is a routine maintenance procedure that checks the magnetic media on each disk drive. Media
Patrol checks all physical drives assigned to disk arrays and spare drives. Media Patrol does not check uncongured
drives.
Media Patrol checks are enabled by default on all disk arrays and spare drives. You can disable Media Patrol in
the disk array and spare drive settings, however that action is not recommended.
Unlike Synchronization and Redundancy Check, Media Patrol is concerned with the condition of the media itself,
not the data recorded on the media. If Media Patrol encounters a critical error, it triggers PDM, if PDM is enabled
on the disk array.
Media Patrol has three status conditions:
• Running–Normal.Youcanaccessyourlogicaldrivesatanytime.
• Yield–Temporarypausewhilearead/writeoperationtakesplace.