Dell PowerVault MD3400 Owner's Manual

Also see for PowerVault MD3400: Getting started guide Deployment guide

Contents

Dell PowerVault MD3400 Owner's Manual Manual pdf 15 page image

Storage Array Thermal ShutdownThe system automatically shuts down when system temperature exceeds the safe threshold. The batterybackup unit protects against data loss by providing power to offload cache to non-volatile memory in theevent of power loss. It is not necessary to shut down any MD1200 Series expansion enclosures attachedto the storage array when thermal shutdown occurs.Temperature threshold values determine the temperature at which shutdown occurs. These thresholdscannot be changed.Table 1. Shutdown Threshold TypeThreshold Temperature Exceeding Event DescriptionNominal failure threshold A critical event is set.Maximum failure threshold Shutdown of the system power supplies occurswithin 3 minutes.Shutdown threshold Shutdown of the system power supplies occurswithin 5 seconds.System Password ResetThe storage array password can be reset if it is forgotten. To reset the password, push and hold down thepassword reset switch for at least 5 seconds. The password is deleted.The RAID controller module allows you to change the password.NOTE: The reset switch can be accessed by using a small object such as the tip of a pen.Cache Functions and FeaturesCache MirroringCache mirroring function copies accepted host-write data from the primary controller to the partnercontroller. This action ensures that host-write data is safely mirrored to the partner controller beforesuccessful completion status is returned to the host. If a controller fails, the surviving controller safelyretains all mirrored data. Cache mirroring is enabled by default.Write-Back CacheIn write-back cache, write operations result in a completion signal being sent to the host operatingsystem as soon as the cache receives the data to be written. The target physical disk receives the data at amore appropriate time to increase controller performance. In dual-active controller configurations withwrite-back caching enabled, the write data is always mirrored to the cache of the second controllerbefore completion status is issued to the host initiator. Write-back cache is enabled by default unlesscache mirroring is disabled.Write-Through CacheIn write-through cache, data is written to the physical disk before completion status is returned to thehost operating system. Write-through cache is considered more robust than write-back cache, since a15