Maximizing Performance - Lenovo ThinkServer RD240 Software User's Manual

RAID
Level Fault Tolerance
6 Combines distributed parity with disk striping. RAID 6 can sustain two drive failures and
still maintain data integrity. Parity provides redundancy for two drive failures without
duplicating the contents of entire drives. If a drive fails, the RAID controller uses the
parity data to reconstruct all missing information. In RAID 6, this method is applied to
entire drives or stripes across all of the drives in a drive group. Using distributed partiy,
RAID 6 offers fault tolerance with limited overhead.
00 Does not provide fault tolerance. All data in a virtual drive is lost if any drive in that
virtual drive fails. Disk striping writes data across multiple drives instead of just one
drive. It involves partitioning each drive storage space into stripes that can vary in size.
RAID 00 is ideal for applications that require high bandwidth but do not require fault
tolerance.
10 Provides complete data redundancy using striping across spanned RAID 1 drive
groups. RAID 10 works well for any environment that requires the 100 percent
redundancy offered by mirrored drive groups. RAID 10 can sustain a drive failure in
each mirrored drive group and maintain drive integrity.
50 Provides data redundancy using distributed parity across spanned RAID 5 drive groups.
RAID 50 includes both parity and disk striping across multiple drives. If a drive fails, the
RAID controller uses the parity data to recreate all missing information. RAID 50 can
sustain one drive failure per RAID 5 drive group and still maintain data integrity.
60 Provides data redundancy using distributed parity across spanned RAID 6 drive groups.
RAID 60 can sustain two drive failures per RAID 6 drive group and still maintain data
integrity. It provides the highest level of protection against drive failures of all of the
RAID levels. RAID 60 includes both parity and disk striping across multiple drives. If a
drive fails, the RAID controller uses the parity data to recreate all missing information.
2.6.2

Maximizing Performance

A RAID disk subsystem improves I/O performance. The RAID drive
group appears to the host computer as a single storage unit or as
multiple virtual units. I/O is faster because drives can be accessed
simultaneously. Table 2.14
level.
RAID Configuration Strategies
describes the performance for each RAID
2-29