Sun Microsystems StorEdge 3000 Series, Installation, Operation And Service Manual

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5-28 Sun StorEdge 3000 Family Installation, Operation, and Service Manual • March 2004
from the drive as large-block, sequential files. Database and transaction-processing
applications read and write data from the drive as small-block, randomly accessed
files.
There are two limitations that apply to the optimization modes:
■
One optimization mode must be applied to all logical drives in an array.
■
Once the optimization mode is selected and data written to logical drives, the
only way to change the optimization mode is to back up all data to another
location, delete all logical configurations of drives, reconfigure the logical drive
with the new optimization mode, and reboot the array.
Note – The maximum allowable size of a logical drive optimized for sequential I/O
is 2 Tbyte. The maximum allowable size of a logical drive optimized for random I/O
is 512 Gbyte. When creating a logical drive that is greater than these limits, an error
message is displayed.
For more information about optimization modes, refer to the Sun StorEdge 3000
Family RAID Firmware User’s Guide for your array.
5.5.6.1 Maximum Number of Disks and Maximum Usable Capacity
for Random and Sequential Optimization
Your choice of random or sequential optimization affects the maximum number of
disks you can include in an array and the maximum usable capacity of a logical
drive. The following tables contain the maximum number of disks per logical drive
and the maximum usable capacity of a logical drive.
Note – You can have a maximum of eight logical drives and 36 disks, using one
array and two expansion units.
TABLE 5-5
Maximum Number of Disks per Logical Drive for a 2U Array
Disk Capacity
(GB) RAID 5
Random RAID 5
Sequential RAID 3
Random RAID 3
Sequential RAID 1
Random RAID 1
Sequential RAID 0
Random RAID 0
Sequential
36.2 14 31 14 31 28 36 14 36
73.4 7 28 7 28 12 30 6 27
146.8 4 14 4 14 6 26 3 13