VessRAID 1000i Series Product Manual
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•
Linux operating systems with the 2.6 kernel support 64-bit LBA. For these
OSes, always choose the default 512 B sector size.
2 TB Limitation
If your Host PC runs Windows 2000 or Windows XP (32-bit), and you want to
create logical drives larger than 2TB, you must choose a sector size larger than
512 B when you create the logical drive. The table below correlates sector size
with logical drive capacity.
Because logical drives can be expanded, you may encounter a situation where
the usable capacity of your expanded logical drive is reduced by the addressing
issue described above. There are two alternatives:
•
Limit your logical drive expansion to within the limits described in the chart.
•
Back up your data, then delete your existing logical drive and create a new
one with a larger sector size.
Cache Policy
As it is used with VessRAID, the term cache refers to any of several kinds of high-
speed, volatile memory that hold data moving from your computer to the physical
drives or vice-versa. Cache is important because it can read and write data much
faster than a physical drive. There are read caches, which hold data as it is read
from a physical drive; and write caches, which hold data as it is written to a
physical drive.
In order to tune the cache for best performance in different applications, user-
adjustable settings are provided. Cache settings are made in conjunction with
logical drives:
•
When you create a logical drive. See “Creating a Logical Drive” on page 121
(WebPAM PROe) or page 167 (CLU)
•
On an existing logical drive. See “Making Logical Drive Settings” on
page 129 (WebPAM PROe) or “Setting Write Cache Policy” on page 172
(CLU)
Logical Drive Size
Sector Size
8 to 16 TB
4096 bytes (4 KB)
4 to 8 TB
2048 bytes (2 KB)
2 to 4 TB
1024 bytes (1 KB)
0 to 2 TB
512 bytes (512 B)
Summary of Contents for VessRAID 1720i
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Page 165: ...Chapter 5 Management with the CLU 149 Figure 4 Controller Status LED Controller Status ...
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