Promise Technology VTRAK 15100, Руководство пользователя

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VTrak 15100 User Manual
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Choosing Stripe Block Size
The stripe block size value can be set to 4KB, 8KB, 16KB, 32KB, and 64KB.
64 KB is the default. This selection will directly affect performance. There are two
issues to consider when selecting the stripe block size.
•
Choose a stripe block size equal to or smaller than the smallest cache buffer
found on any disk drive in your logical drive. A larger value slows the logical
drive down because disk drives with smaller cache buffers need more time
for multiple accesses to fill their buffers.
• If your data retrieval consists of fixed-size data blocks, such as some
database and video applications, choose that data block size as your stripe
block size.
Generally speaking, email, POS and webservers prefer smaller stripe block
sizes. Video and database applications prefer larger stripe block sizes.
Gigabyte Boundary
The Gigabyte Boundary feature is designed for logical drives in which a drive has
failed and the user cannot replace the drive with the same capacity or larger.
Instead, the Gigabyte Boundary feature permits the installation of a replacement
drive that is slightly smaller (within 1 gigabyte) than the remaining working drive
(for example, an 80.5GB drive would be rounded down to 80GB). This can be
helpful in the event that a drive fails and an exact replacement model is no longer
available. With VTrak, this feature is always enabled.
Initialization
Initialization is the process of setting all of the data bits on all of the disk drives to
zero. This has the effect of erasing any existing data from the drives. This action
is especially helpful in creating accurate parity in logical drives with more than
four drives.
Initialization applies to RAID 1, 3, 5, 10 and 50. If you create one of these logical
drives automatically, the logical drive is always initialized. If you create the logical
drive manually, you can choose whether to initialize.
The initialization process begins immediately after the logical drive is created and
may take some time to finish, depending on the size of the disk drives in your
logical drive. VTrak displays initialization progress on the LCD screen. When
initialization is done, VTrak restarts automatically.