vsphere-esxi-vcenter-server-55-storage-guide

vSphere StorageTable 16‐5. VOMA Command OptionsCommand OptionDescription-m | --module The module to run: vmfs or lvm. If you specify vmfs,minimal checks are performed for LVM as well. Thedefault module is vmfs.-f | --func Functions to be performed:query - list functions supported by module.check - check for errors.-d | --device Device or disk to be inspected. Make sure to provide theabsolute path to the device partition backing the VMFSdatastore. For example, /vmfs/devices/disks/naa.00000000000000000000000000:1.-s | --logfile Specify the log file to output the results.-v | --version Display the version of VOMA.-h | --help Display the help message for the VOMA command.Configuring VMFS Pointer Block CacheYou can use advanced VMFS parameters to configure pointer block cache.As the size of virtual machine files on VMFS datastores increases, the number of pointer blocks used bythose files also increases. Pointer blocks are used to address file blocks in large virtual machine files andvirtual disks on a VMFS datastore.You can configure the minimum and maximum sizes of the pointer block cache on each ESXi host. When thesize of the pointer block cache approaches the configured maximum size, an eviction mechanism removessome pointer block entries from the cache to allow for new pointer blocks to be read in.Base the maximum size of the pointer block cache on the working size of all open virtual disk files thatreside on VMFS datastores. All VMFS datastores on the host use a single pointer block cache.The minimum value is based on the minimum guaranteed memory that the system can allocate to the cache.1TB of open file space requires approximately 4MB of memory.Use the following parameters to configure the minimum and maximum values for pointer block cache.Table 16‐6. Advanced Parameters to Regulate Pointer Block CacheParameter Values DescriptionVMFS3.MaxAddressableSpaceTB Default value is 32 (in TB). Maximum size of all open files thatVMFS cache will support beforeeviction starts.VMFS3.MinAddressableSpaceTB Default value is 10 (in TB). Minimum size of all open files thatVMFS cache guarantees to support.For information about how to configure these advanced parameters, see “Set Advanced Host Attributes inthe vSphere Web Client,” on page 131.Set Advanced Host Attributes in the vSphere Web ClientYou can set advanced attributes for a host.CAUTION Changing advanced options is considered unsupported unless VMware technical support or a KBarticle instruct you to do so. In all other cases, changing these options is considered unsupported. In mostcases, the default settings produce the optimum result.152 VMware, Inc.