Users Guide

● Edit Cache Policy — You can change the cache policy for the following options:
○ Read Policy — Following values are available for selection:
￭ Adaptive Read Ahead — Indicates that for the given volume, the control uses the Read-Ahead cache policy if
the two most recent disks accesses occurred in sequential sectors. If the read requests are random, the controller
returns to No Read Ahead mode.
￭ No Read Ahead — Indicates that for the given volume, no read ahead policy is used.
￭ Read Ahead — Indicates that for the given volume, the controller reads sequentially ahead of the requested data
and stores the additional data in cache memory, anticipating a data requirement. This speeds up sequential data
reads, but there is less improvement when accessing random data.
○ Write Policy — Change the write cache policy to one of the following options:
￭ Write Through — Indicates that for the given volume, the controller sends a data transfer completion signal to
the host system when the disk subsystem has received all the data in a transaction.
￭ Write Back — Indicates that for the given volume, the controller sends a data transfer completion signal to the
host system when the controller cache has received all the data in a transaction. The controller then writes the
cached data to the storage device in the background.
￭ Force Write Back — When using force write-back caching, the write cache is enabled regardless of whether the
controller has a battery. If the controller does not have a battery and force write-back caching is used, data loss
may occur in the event of a power failure.
○ Disk Cache Policy — Change the disk cache policy to one of the following options:
￭ Default — Indicates that the disk is using its default write cache mode. For SATA disks, this is enabled and for
SAS disks this is disabled.
￭ Enabled — Indicates that the disk’s write cache is enabled. This increases performance and the probability of
data loss if there is power loss.
￭ Disabled — Indicates that the disk’s write cache is disabled. This decreases performance and the probability of
data loss.
● Edit Disk Capacity — You can add the physical disks to the selected virtual disk in this window. This window also
shows the current capacity and new capacity of the virtual disk after adding the physical disks.
● RAID Level Migration — Displays the Disk Name, Current RAID Level, and size of the virtual disk. Allows you to select a
New RAID Level. User may have to add additional drives to existing Virtual disks to migrate to new raid level. This feature
is not applicable on RAID 10, 50 and 60.
● Initialize: Fast — Updates the metadata on the physical disks so that all the disk space is available for future write
operations. The initialize option can be completed quickly because existing information on the physical disks is not erased,
although future write operations overwrites any information that remains on the physical disks.
● Initialize: Full — All existing data and file systems are erased.
NOTE: The Initialize: Full option is not applicable for PERC H330 controllers.
● Check Consistency — To check the consistency of a virtual disk, select Check Consistency from the corresponding
drop-down menu.
NOTE: Consistency check is not supported on drives set up in RAID0 mode.
For more information about these options, see the iDRAC Online Help.
4. Click Apply Now to apply the changes immediately, At Next Reboot to apply the changes after next reboot, At Scheduled
Time to apply the changes at a particular time, and Discard All Pending to discard the changes.
Based on the selected operation mode, the settings are applied.
Managing virtual disks using RACADM
Use the following commands to manage virtual disks:
● To delete virtual disk:
racadm storage deletevd:<VD FQDD>
● To initialize virtual disk:
racadm storage init:<VD FQDD> -speed {fast|full}
● To check consistency of virtual disks (not supported on RAID0):
racadm storage ccheck:<vdisk fqdd>
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Managing storage devices