Adaptec 2169400-R User Guide - Page 73

Changing the Read Cache Setting, Changing the Initialize Priority, Enabled, Disabled, Actions

Page 73 highlights

Chapter 6: Managing Logical Drives and Hot Spares ● 73 Changing the Read Cache Setting When read caching is enabled, the controller monitors the read access to a logical drive and, if it sees a pattern, pre-loads the cache with data that seems most likely to be read next, increasing performance. ● Enabled-The controller transfers data from the logical drive to its local cache in portions equal to the stripe size. Use this setting for the best performance when workloads are steady and sequential. Enabled is the default setting. ● Disabled-The controller transfers data from the logical drive to its local cache in portions equal to the system I/O request size. Use this setting for the best performance when workloads are random or the system I/O requests are smaller than the stripe size. (For more information about system I/O requests, refer to your operating system documentation.) To quickly change the read cache setting: 1 Click the logical drive you want. 2 In the menu bar, select Actions, click Configure read cache, then select Enabled or Disabled as required. The read cache setting is changed. Changing the Initialize Priority The Initialize Priority setting determines the priority for the initialization of the logical drive. The default setting is High, which means that the logical drive is initialized as quickly as possible. Changing the Initialize Method The Initialize Method setting determines how a logical drive is initialized (prepared for reading and writing), and how long initialization will take. The settings are presented in order of slowest to fastest method. ● Build-(slowest) For RAID 1 logical drives, data is copied from the primary drive to the mirror drive; for RAID 5 logical drives, parity is computed and written. Build is the default setting for most logical drives (see Quick method below). Adaptec Storage Manager performs build initializations in the background; you can use the logical drive immediately. ● Clear-Every block in the logical drive is overwritten, removing all existing data. You can't use the logical drive until the initialization is complete. ● Quick-(fastest) The logical drive is made available immediately. Quick is the default setting for RAID 1, RAID 1EE, and RAID 10 logical drives.

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Chapter 6: Managing Logical Drives and Hot Spares
73
Changing the Read Cache Setting
When
read caching
is enabled, the controller monitors the read access to a logical drive and, if it
sees a pattern, pre-loads the cache with data that seems most likely to be read next, increasing
performance.
Enabled
—The controller transfers data from the logical drive to its local cache in portions
equal to the stripe size. Use this setting for the best performance when workloads are
steady and sequential.
Enabled
is the default setting.
Disabled
—The controller transfers data from the logical drive to its local cache in portions
equal to the system I/O request size. Use this setting for the best performance when
workloads are random or the system I/O requests are smaller than the stripe size. (For
more information about system I/O requests, refer to your operating system
documentation.)
To quickly change the read cache setting:
1
Click the logical drive you want.
2
In the menu bar, select
Actions
,
click
Configure read cache
, then select
Enabled
or
Disabled
as required.
The read cache setting is changed.
Changing the Initialize Priority
The Initialize Priority setting determines the priority for the initialization of the logical drive.
The default setting is
High
, which means that the logical drive is initialized as quickly as
possible.
Changing the Initialize Method
The Initialize Method setting determines how a logical drive is
initialized
(prepared for reading
and writing), and how long initialization will take. The settings are presented in order of
slowest to fastest method.
Build
—(slowest) For RAID 1 logical drives, data is copied from the primary drive to the
mirror drive; for RAID 5 logical drives, parity is computed and written.
Build
is the default
setting for most logical drives (see
Quick
method below).
Adaptec Storage Manager performs build initializations in the background; you can use
the logical drive immediately.
Clear
—Every block in the logical drive is overwritten, removing all existing data. You can’t
use the logical drive until the initialization is complete.
Quick
—(fastest) The logical drive is made available immediately.
Quick
is the default
setting for RAID 1, RAID 1EE, and RAID 10 logical drives.