Setting up SmartIO read caching for VxVM volumes

1. Create a VxVM type cache area on an SSD device, using one of the following commands:

   • Specify one or more devices using the disk access name (daname) of the device. The device should be initialized for VxVM use and have the cdsdisk format.

     # sfcache create -t VxVM [size] daname[...] \
     [cacheline_size=cacheline_size] [--auto|--noauto] [--nostripe|ncols=N] [cachearea_name]

     Where:

     daname specifies the disk access name of the device on which to create the cache area.

     cachearea_name specifies a customized name for the cache area. If unspecified, the SmartIO feature automatically generates a name for the cache area.

     size specifies the size for the cache area. By default, the cache area uses all of the available space on the device.

     --noauto|--auto specifies the type of cache area. The default is --auto.

     --nostripe|ncols=n specifies the layout options for the cache area. By default, the cache area is created over a striped volume if two or more disks are specified. Use the ncols=n option to specify the number of columns for the striped volume. Use the --nostripe option to create the cache area on a concatenated volume over the specified disks.

     cacheline_size specifies the unit that SmartIO uses for caching. When the application I/O accesses the data, the SmartIO moves the data to the cache according to the cacheline size. Generally, you do not need to change the cacheline_size.

     For example:

     # sfcache create -t VxVM ssd0_0

   • Alternatively, you can specify the name of a disk group and a volume to use for the cache area. In this case, you cannot specify a size: the cache area uses the entire volume.

     # sfcache create -t VxVM  [cacheline_size=cacheline_size] \
      [--noauto|--auto] dg/vol

     Where:

     dg/vol specifies the disk group name and volume name that you want to use for the cache area. SmartIO uses this name for the cache area.

     --noauto|--auto specifies the association type of the cache area. The default is --auto.

     For example:

     # sfcache create -t VxVM --auto ssd_dg/ssd_vol

2. Enable caching for the required VxVM volumes. If the cache area is auto, this step is not required. Caching is enabled by default when the SSD device comes online, for any VxVM volumes.

   If the cache area is noauto, you must enable caching for the volumes to be cached.

   # sfcache enable [--read] dg/vol 

   Where:

   dg/vol specifies the disk group name and volume name of the volume that you want to cache.

   For example:

   # sfcache enable mydg/vol1