Manuals

Hardware Parameters
Physical Parameters
Default Rebuild Rate
Stripe Size
SCSI Transfer Parameters
Data Transfer Rated
Command Tagging
Startup Parameters

Once this option is selected, a screen similar to Edit/View Parameters is displayed. This screen has two options: one for setting hardware parameters and the other for setting physical parameters for the DAC960PL controller.

Hardware Parameters

Once this option is selected, a screen similar to Hardware Parameters is displayed. At present, the only hardware parameter that is supported is the battery backup. This option should only be enabled on a DAC960PL controller that has a battery backup unit.

Physical Parameters

Once this option is selected, a screen similar to Physical Parameters is displayed. At present, the two physical parameters that can be set are the default rebuild rate and the stripe size.

Default Rebuild Rate

This option is used to change the rebuild rate from 0 to 50. A rebuild rate of 50 is the maximum that can be defined. Generally, a higher rebuild rate value would result in the controller spending more time doing rebuild than other activities, resulting in a faster drive rebuild but slower disk performance. If rebuild needs to be given the least priority, to speed other activities, set the rebuild rate to 0. This parameter can also be set using the DAC administrative utilities under various operating systems.

Stripe Size

CAUTION: Stripe size changes will result in complete loss of all data.

This option is used to change, and thereby speed up, the way the information is accessed on the drives connected to the DAC960PL. Stripe sizes of 8 K, 16 K, 32 K, and 64 K are supported at present. A higher stripe size would normally result in a higher sequential throughput and a slightly reduced random throughput. Whenever this option is used to select a different stripe size, the existing data on the drives will be lost. Therefore, before changing the stripe size, make sure all useful data is backed up. Also, when saving the new stripe size, if any warning message is displayed, it is highly recommended that a new configuration be performed after the new stripe size is saved.

SCSI Transfer Parameters

After selecting this option, a window will be displayed asking the user to enter a channel number. After entering the channel number (0 or 1) whose parameters you want to change or view, a windows will be displayed similar to SCSI Transfer Parameters . These options are set separately for each SCSI channel.

Data Transfer Rate

This option sets the default SCSI negotiation rate for the selected SCSI channel. The options are: 10 MHz, 8 MHz, 5 MHz, and ASYNCHRONOUS.

Command Tagging

This option enables or disables command tagging support for the selected SCSI channel. This option may increase performance, but is not supported by many older drives.

Startup Parameters

Once this option is selected, a screen similar to Startup Parameters is displayed. These options (SPIN UP OPTION, DEVICES PER SPIN, and DELAY) set the way that the SCSI devices will initially spin up. The settings for these options depend on the desired method for spinning up the SCSI drives. The spin-up options are:

Automatic--The DAC960PL spins up the number of drives specified under DEVICES PER SPIN, waits for DELAY, then repeats this sequence until all drives are spinning.

On Power--The DAC960PL assumes that the drives spin up themselves when power is applied; thus, it does not assume any spin-up command.

NOTE: These options only apply to SCSI drives and do not apply to other SCSI devices. These devices should always be set to begin spinning on at power up.