3Ware 9550SXU-8LP User Guide - Page 104

Chapter 6. 3ware Disk Manager (3DM 2) Background Task Rate The Background Task Rate fields let you change the balance of background tasks and I/O performed by the controller. 9000-series controllers show separate settings for Rebuild/Migrate Rate and Verify Rate, as shown in Figure 41. The Rebuild/Migrate Rate also applies to initialization. Although the same rate is used for rebuilding, migrating, and initializing, migrating has the highest priority. 7000- and 8000-series controllers show only one setting for Task Rate; it applies to both rebuild and verify rates. Note that this rate is not persistent following a reboot for 7/8000 controllers. The five radio buttons let you set the ratio at which background tasks are performed in comparison to I/O. The furthest left buttons set the firmware to the fastest settings for background tasks settings. This means, maximum processing time will be given to background tasks rather than I/O. The furthest right buttons set the firmware to the slowest background rates, giving maximum processing time to I/O. For additional information, see "About Background Tasks" on page 177. Unit Policies For units on 9000-series controllers, you can enable or disable these policies: Write Cache, Auto-verify, and Continue on Source Error During Rebuild. For 9550SX and 9590SE controllers, you can also enable or disable Queuing, and select a StorSave Profile. 3DM lists each unit on the controller specified in the drop-down list on the menu bar, and shows you whether the policies are currently enabled or disabled for each unit. This section does not appear for 7000- and 8000- series controllers. Unit Write Cache. You can enable or disable write cache for each unit. 3DM lists each unit on the controller specified in the drop-down list on the menu bar, and shows you whether the write cache is currently enabled or disabled for it. Write cache is a combination of the physical hard drives' write cache as well as the controller's memory, depending on what type of unit you are using. For 9500S controllers, a Disable Write Cache on Unit Degrade setting can be set in 3ware BIOS Manager (3BM). You can see if this setting is enabled in the Other Controller Settings field at the bottom of this Controller Settings page. If Disable Write Cache on Unit Degrade is enabled, upon degrade of a unit, the write cache will automatically be disabled, even if you enable write cache in the Unit Write Cache field. (This option does not apply to 9550SX and 9590SE controllers; the feature is integrated into the StorSave policy.) For additional information, see "Enabling and Disabling the Unit Write Cache" on page 143. 94 3ware Serial ATA RAID Controller User Guide