Logical unit settings for the EMC CLARiiON

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Logical unit (LU) settings are configurable at the LU level.

Table 1 lists the options that must be set for each LU that the system accesses. LUs that are accessed by hosts can be configured differently.

Table 1. EMC CLARiiON LU settings that the system supports
Option EMC CLARiiON default setting Required system setting
LU ID Auto N/A
RAID Type 5 Any RAID Group
RAID Group Any available RAID Group Any available RAID Group
Offset 0 Any setting
LU Size ALL LBAs in RAID Group Any setting
Placement Best Fit Either Best Fit or First Fit
UID N/A N/A
Default Owner Auto N/A
Auto Assignment Disabled Disabled
Verify Priority ASAP N/A
Rebuild Priority ASAP N/A
Strip Element Size 128 N/A
Read Cache Enabled Enabled Enabled
Write Cache Enabled Enabled Enabled
Idle Threshold 0–254 0–254
Max Prefetch Blocks 0–2048 0–2048
Maximum Prefetch IO 0–100 0–100
Minimum Prefetch Size 0–65534 0–65534
Prefetch Type 0, 1, or 2 0, 1, or 2
Prefetch Multiplier 0 - 2048 or 0 - 324 0 - 2048 or 0 - 324
Retain prefetch Enabled or Disabled Enabled or Disabled
Prefetch Segment Size 0 - 2048 or 0 - 32 0 - 2048 or 0 - 32
Idle Delay Time 0 - 254 0 - 254
Verify Priority ASAP, High, Medium, or Low Low
Write Aside 16 - 65534 16 - 65534
Note: The system cannot obtain or change the configuration options that are listed in the preceding table. You must configure these options yourself.