Wiebetech SS8 User Manual

 

   

W i e b e T e c h   L L C  

 

SCSI Accessed Fault-Tolerant Enclosures 

SAF-TE commands are used to monitor information about the  
status of the drives in the array, such as rebuilding, failed,  
and spare. SAF-TE also monitors certain environmental  
information about the system such as temperature, voltage,  
power supply, and fan health. 

Small Computer System Interface 

Self-Monitoring, Analysis and Reporting Technology 

Monitoring tool to display drive’s health status. 

Spare Disk 

A disk that is assigned that be a spare is used automatically  
to replace a failed drive in a RAID array or a Volume Group. 
Spare disks remain idle until the systems detects a failed 
drive. 

Dedicated Spare disks 

 

These are spare disks that only belong to only one specified 
VG for recovery/rebuilding.  

The Global Spare disks are accessible by all VGs to do  
rebuilding/recovery. 

User Data Volume 

Each VG could be divided into different UDVs. The UDVs  
from one VG share the same RAID level, but may have  
different volume capacity. 

Volume Group

 

A Volume Group is a RAID array that consists of multiple  
physical disks. 

Write-Back cache write policy

  

A caching method that delays copying data modification to  
system memory until absolutely necessary. This method  
offers a better performance than write-through method, but at  
the risk of losing the modifications if the system crashes. 

Write-Through cache write policy 

A caching method that writes data modifications to both the  
cache memory and system memory. This method provides  
data consistency between the cache and system memory, but  
at a slower performance than the write-back method. 

World Wide Name (WWN)

  

Also known as World Wide Identifier (WWID). WWN is an  
unique identifier created for each physical disk in a Fibre  
Channel storage network.