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Changing Controller ParametersUse this option to modify the parameters for the array controller.
Controller Name. If the controller name needs to be set, select Controller Name and type the desired name. Click OK to save the change. Controller Unique ID. The Controller Unique ID is automatically set. The tabs in this window include: Network Tab
Some of the options on the Change Controller Parameters window
require that the controller be reset so the changes can take effect. For
details about saving changes in the Change Controller Parameters window,
see Saving Changed Values.
The Change Channel Settings window is displayed. For the server to recognize the array, a host channel must have an ID assigned to a logical drive and a logical drive mapped to that host channel and ID. This window enables you to configure the host/drive channel.
NOTE: Depending on the controller configuration, you might need to select both primary and secondary channel IDs as described in the following steps.
Changing Host ID in a Fibre Configuration
The type of application the array is working with determines whether Random or Sequential I/O should be applied. Video/imaging application I/O size can be 128, 256, 512 Kbyte, or up to 1 Mbyte, so the application reads and writes data to and from the drive as large-block, sequential files. Database/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:
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. See also Write-Back Cache and Maximum Number of Disks and Maximum Usable Capacity for Random and Sequential Optimization.
If an existing logical drive was created with Optimization set for Random I/O, the same logical drive is not be capable of reading or writing data when changed to sequential mode. The reverse is also true because the stripe size is different for each.
Normally, errors might occur when a hard drive writes data. To avoid the write error, the controller can force the hard drives to verify the written data.
The RAID controller provides a background rebuilding ability. This means the controller is able to serve other I/O requests while rebuilding the logical drives. The time required to rebuild a drive set largely depends on the total capacity of the logical drive being rebuilt. Additionally, the rebuilding process is totally transparent to the host computer or the operating system.
The SCSI Motor Spin-Up decides how the SCSI drives in a Disk Array are started. When the power supply is unable to provide sufficient current for the hard drives and controllers that are powered up at the same time, spinning up the hard drives serially is one of the best ways to consume lower powerup current. By default, all hard drives spin up when powered on.
By default, when the controller is powered up, it sends a SCSI bus reset command to the SCSI bus. When disabled, it does not send a SCSI bus reset command on the next power up. When connecting dual host computers to the same SCSI bus, the SCSI bus reset interrupts all the read/write requests being performed. This might cause some operating systems or host computers to act abnormally. Disable Power Up SCSI Reset at power up to avoid this situation.
This function sets the delay time before the controller tries to access the hard drives after power on. The default is 15 seconds.
This is the maximum number of tags that can be sent to each drive at the same time. A drive has a built-in cache that is used to sort all of the I/O requests (tags) that are sent to the drive, enabling the drive to finish the requests faster. The cache size and maximum number of tags varies between different brands and models of drive. Use the default setting of 32. Changing the maximum tag count to Disable causes the internal cache of the drive to be ignored (not used). The controller supports tag command queuing with an adjustable tag count from 1 to 128.
The SCSI I/O Timeout is the time interval for the controller to wait for a drive to respond. If the controller attempts to read data from or write data to a drive but the drive does not respond within the SCSI I/O timeout value, the drive is considered a failed drive. The SCSI I/O Timeout is the time interval for the controller to wait for a drive to respond. If the controller attempts to read data from or write data to a drive but the drive does not respond within the SCSI I/O timeout value, the drive is considered a failed drive. The default setting for SCSI I/O Timeout is 15 seconds for the SCSI array and 30 seconds for the Fibre Channel array. CAUTION: Do not change this setting. Setting the timeout to a lower value causes the controller to judge a drive as failed while a drive is still retrying or while a drive is unable to arbitrate the SCSI bus. Setting the timeout to a greater value causes the controller to keep waiting for a drive, and it might sometimes cause a host timeout. When the drive detects a media error while reading from the drive platter, it retries the previous reading or recalibrates the head. When the drive encounters a bad block on the media, it reassigns the bad block to another spare block. However, all of this takes time. The time to perform these operations can vary between different brands and models of drives. During SCSI bus arbitration, a device with higher priority can use the bus first. A device with lower priority sometimes receives a SCSI I/O timeout when devices of higher priority keep using the bus. The Periodic Drive Check Time is an interval for the controller to check the drives on the SCSI bus. The default value is Disabled, which means if there is no activity on the bus, the controller does not know if a drive has failed or has been removed. Setting an interval enables SANscape to detect a drive failure when there is no array activity; however, performance is downgraded.
This function enables you to configure the maximum size of the I/O queue the controller can accept from the host computer by byte size. The default is 256. The predefined range is from 1 to 1024 bytes, or you may choose the Auto Computer (Automatically Configured) mode. This function is used to change the number of LUNs per host SCSI ID. The default setting is 32 LUNs, with a predefined range of 1 to 32 LUNs available.
Three information-only fields are displayed: Controller Configuration, Controller Status, and the Secondary Serial No. fields.
NOTE: Set both controllers in the Redundant Primary configuration. The controllers then determine which one is primary and which one is secondary. This prevents any possible conflicts between controllers.
Some of the options on the Change Controller Parameters window require that the controller be reset so that the changes take effect. If a change requires a controller reset, the following message is displayed in the lower left side of the window: [Controller reset is required for changes to take effect.] To reset the controller and save changed values, you can either select the Issue Controller Reset check box at the time of making the change, or reset the controller later through the Controller Maintenance window. If you are making multiple changes, you might not want to stop and reset the controller after each change. If you do not select the Issue Controller Reset check box, and the change requires a reset, when you click OK, a warning message is displayed.
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