Managing Flash Accel caching systems : Setting the cache mode for virtual machines and disks

Setting the cache mode for virtual machines and disks
The cache mode determines how storage reads and writes are serviced by Flash Accel. You can use Write Thru mode for caching reads and writes, Write Around mode for caching reads only, and Pass Thru mode when you want to keep the cache "warm" without inserting into or reading from the cache. You set the cache mode on both the disk and the virtual machine on which the disk is configured.
About this task 
Three cache modes are available:
In Write Thru mode (the default), read data is written to cache and read requests are serviced from cache. Write data is written to the storage system, then to cache. Write Thru is the optimal setting for Flash Accel when the product is used for read-intensive applications.
In Write Around mode, read data is written to cache and read requests are serviced from cache. Write data is written to the storage system but not to cache.
In Pass Thru mode, no data is cached and no I/O is serviced from cache. The cache is kept warm for virtual disks. It remains populated with data from previous application read and write activity.
You can set cache modes differently for virtual machines and disks, and for disks on the same virtual machine. The following logic determines the active cache mode when the setting differs on a virtual machine and disks:
The virtual machine cache mode overrides the disk cache mode if the disk setting is higher.
So:
If the cache mode is set to Pass Thru on the virtual machine and Write Around or Write Thru on disks, the disks operate in Pass Thru mode.
If the cache mode is set to Write Thru on the virtual machine, the disks operate in whichever mode you have set them to.
Steps 
1.
From the home page of the FAMC, click the wrench icon for the VM on which you want to set the cache mode and select Cache Mode > mode.
From the home page of the FAMC, select each VM on which you want to set the cache mode and click Cache Mode in the Bulk Actions area of the FAMC. In the cache mode dialog box, select the button for the cache mode and click Submit.
Note: Select Advanced in the wrench tool menu or Bulk Actions area to enable or disable caching, set the cache mode, and enable or disable cache metrics for VMs or disks in the same step.
2.
Note: You can view the disks for a VM by opening the details page for the VM. FAMC displays a Show Me menu in the left pane. Click VM Disks to navigate to the disks page.
From the disks page of the Flash Accel Management Console, click the wrench icon for the disk on which you want to set the cache mode and select Cache Mode > mode.
From the disks page of the Flash Accel Management Console, select each disk on which you want to set the cache mode and click Cache Mode in the Bulk Actions area of the FAMC. In the cache mode dialog box, select the button for the cache mode and click Submit.
Result 
The Cache Mode for the virtual machine and disks is set to the specified mode.
Parent Topic: Managing Flash Accel caching systems