User Manual

Accusys 75170
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This chapter contains includes all the information about RAID
level and preparing for installation. You will find:
 A full introduction to and comparison of RAID level 1



Important notices on the safe operation and installation of
ACS-75170
Pre-installation planning
RAID 1
The ACS-75170 can support the following RAID level 1. RAID 1 is commonly referred to as
Disk Mirroring, Disk Shadowing or Disk Duplexing as all data is duplicated across both disks.
RAID 1 can only be performed with two hard drives (with four drives, RAID 0+1 is configured
automatically). As data is identical on both disks, storage capacity is that of the smaller disk.
RAID 1 has poor performance for write operations but very high performance for read
intensive operations. Further information on RAID concepts can be found in Appendix B,
Glossary.
RAID 1: Mirroring
Characteristics: Recommended use:
 Better Read transaction rate then single disks,
same Write transaction rate as single disks.
 100% redundancy of data means no rebuild of
data is necessary in case of disk failure, just a
copy to the replacement disk.
 All the disks have the same data.
 Raid level 1 requires two drives.
 Storage capacity = Capacity of smaller disk
 Accounting
 Payroll
 Financial
 Any application
requiring high
availability