Infortrend RAID Controller Manual

8-2
mode is to backup all data to somewhere else, delete all logical
configurations of drives, and reboot system.
The limitation derives from the consideration with the redundant
configuration of controllers. Data inconsistency might occur when a
controller pre-configured with optimization mode is used to replace a
failed controller with different mode.
Database and Transaction-based Applications: this kind of
applications usually include SQL server, Oracle server, Informix, or
other data base services. These applications keep each transaction
within the minimal size, so that I/O transfers will not be clogged by
one large transaction. Due to its transaction-based nature, these
applications do not read or write a bunch of data in a sequential
order. Instead, access to data occurs randomly. The transaction size
ranges from 2K to 4K. Transaction-based performance is usually
measured in “I/Os per second” or “IOPS.”
Video Recording/Playback and Imaging Applications: this kind of
application usually belongs to video playback, video post-production
editing, or other similar applications. These applications read or
write large files from and into storage in a sequential order. The size
of each I/O can be 128K, 256K, 512K, or up to 1MB. Performance is
measured in “MB/Sec.”
When an array works with applications such as video or image
oriented applications, the application reads/writes from the drive as
large-block, sequential files instead of small-block and randomly
accessed files.
1. Optimization for Random I/O: the logical drive, cache memory,
and other controller parameters will be adjusted for the use of
database/transaction-processing applications.
2. Optimization for Sequential I/O:
“Optimization for Sequential I/O” provides larger stripe size (block
size, also known as Chunk size) than “Optimization for Random
I/O.” Numerous controller’s internal parameters will also be
changed to optimize for sequential or random I/O. The change will
take effect after the controller resets.
The logical drive, cache memory, and other controller internal
parameters will be adjusted for the use of video/imaging
applications.
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