Specifications

SCSI to SATA RAID Subsystem | Administrator’s Manual Host-side and Drive-side Parameters | en 141

Bosch Security Systems F.01U.027.802 | V1 | 2006.11

8.2.3 Maximum Tag Count: Tag Command Queuing (TCQ) and Native Command

Queuing (NCQ) Support

Fig. 8.14 Selecting Maximum Tag Count

This sub-menu facilitates the support for both Tagged Command Queuing (TCQ) and Native

Command Queuing (NCQ). TCQ is a traditional feature on SCSI or Fibre disk drives, while

NCQ is recently implemented with SATA disk drives. The queuing feature requires the support

of both host adapters and hard disk drives. Command queuing can intelligently reorder host

requests to streamline random accesses for IOPS/multi-user environments.

Bosch’s subsystems support tag command queuing with an adjustable maximum tag count

from 1 to 128. The default setting is “Enabled” with a maximum tag count of 32 (SCSI or Fibre

drives) or 16 (default for SATA drives). Choose “Maximum Tag Count”, then press [ENTER]. A

list of available tag count numbers displays. Move the cursor bar to a number, then press

[ENTER]. Choose Yes in the dialog box that follows to confirm the setting.

NOTICE!

• Every time you change this setting, you must reset the controller for the changes to take

effect.

• Disabling Tag Command Queuing will disable the hard drives’ built-in cache for Write-

Back operation.

• The following options are categorized as related to array maintenance and data integrity:

– Periodic Drive Check Time

– Periodic Auto-Detect Failure Drive Swap Check Time

– Auto-Assign Global Spare Drive

Details of these options see Section 10 Data Integrity.

• Another option is associated with disk drive SMART support. Details see

Section 12 S.M.A.R.T. Configuration.

– Drive Predictable Failure Mode (SMART