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

vSphere Storage5 Specify the amount of virtual flash resource to reserve for swapping to host cache.6 Click OK.Configure Flash Read Cache for a Virtual MachineYou can configure Flash Read Cache for a virtual machine compatible with ESXi 5.5 or later.Enabling Flash Read Cache lets you specify block size and cache size reservation.Block size is the minimum number of contiguous bytes that can be stored in the cache. This block size can belarger than the nominal disk block size of 512 bytes, between 4KB and 1024KB. If a guest operating systemwrites a single 512 byte disk block, the surrounding cache block size bytes will be cached. Do not confusecache block size with disk block size.Reservation is a reservation size for cache blocks. There is a minimum number of 256 cache blocks. If thecache block size is 1MB, then the minimum cache size is 256MB. If the cache block size is 4K, then theminimum cache size is 1MB.For more information about sizing guidelines, search for the Performance of vSphere Flash Read Cache inVMware vSphere 5.5 white paper on the VMware web site.PrerequisitesVerify that the virtual machine is compatible with ESXi 5.5 or later.Procedure1 To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.2 Click the Related Objects tab and click Virtual Machines.3 Right-click the virtual machine and select Edit Settings.4 On the Virtual Hardware tab, expand Hard disk to view the disk options.5 To enable Flash Read Cache for the virtual machine, enter a value in the Virtual Flash Read Cache textbox.6 Click Advanced to specify the following parameters.OptionReservationBlock SizeDescriptionSelect a cache size reservation.Select a block size.7 Click OK.Remove Virtual Flash ResourceYou might need to remove a virtual flash resource on a local SSD to use the device for another resource,such as Virtual SAN.You cannot remove a virtual flash resource if it is configured with host swap cache or if the host has virtualmachines configured with Flash Read Cache that are powered on.Procedure1 In the vSphere Web Client, navigate to the host that has virtual flash configured.2 Click the Manage tab and click Settings.3 Under Virtual Flash, select Virtual Flash Resource Management and click Remove All.After you remove the virtual flash resource and erase the SSD, the disk is available for other operations.208 VMware, Inc.