InfoScale™ 9.0 SmartIO for Solid-State Drives Solutions Guide - Solaris

Last Published:
Product(s): InfoScale & Storage Foundation (9.0)
Platform: Solaris
  1. Introducing SFHA Solutions SmartIO
    1.  
      About SmartIO for solid-state drives
    2.  
      About SmartIO in an SFHA environment
    3.  
      About SmartIO in an Active/Active cluster environment
    4. About SmartIO in the Solaris virtualized environments
      1.  
        Performing live migration between LDOMs in the SmartIO environment
    5.  
      About the SmartIO caching profiler tool
  2. Using the SmartIO feature: use cases
    1. About SmartIO read caching for applications running on VxVM volumes
      1.  
        Required configuration for SmartIO read caching for VxVM volumes
      2.  
        Automatic caching for VxVM volumes
      3.  
        Setting up SmartIO read caching for VxVM volumes
      4.  
        Verifying the VxVM cache area and monitoring the caching
    2. About SmartIO read caching for applications running on VxFS file systems
      1.  
        Required configuration for SmartIO read caching for a VxFS file system
      2.  
        Automatic caching for VxFS file systems
      3.  
        Setting up SmartIO read caching for VxFS file systems
      4.  
        Verifying the VxFS cache area and monitoring the caching
      5.  
        Customizing the caching behavior
    3. About SmartIO caching on SSD devices exported by FSS
      1.  
        Status of cache areas when nodes leave or join the cluster
      2.  
        Setting up cache areas using SSDs exported by FSS
    4. About SmartIO write-back caching for applications running on VxFS file systems
      1.  
        Required configuration for SmartIO write-back caching for a VxFS file system
      2.  
        Setting up SmartIO write-back caching for VxFS file systems
      3.  
        Verifying the VxFS cache area and monitoring the caching (writeback mode)
    5. About multiple SmartIO cache areas for read and write-back caching on VxFS file systems
      1.  
        About the smartiocache option
      2.  
        Converting VxFS cache areas from one type to another
      3.  
        Setting up multiple cache areas on a system
      4.  
        Verifying the VxFS cache areas
    6. About SmartIO caching for Oracle databases on VxFS file systems
      1.  
        Prerequisites and configuration for using the SmartIO plug-in for Oracle
      2.  
        Setting default SmartIO caching policies for a database running on a VxFS file system
      3.  
        Setting SmartIO caching policies for database objects
      4.  
        Pinning and unpinning database objects
      5.  
        Enabling and disabling caching for the database
      6.  
        Listing cache policy details for the database
      7.  
        Listing cache statistics for the database
    7. About SmartIO caching for databases on VxVM volumes
      1.  
        Applying a SmartIO database caching template for a VxVM volume
  3. Administering SmartIO
    1.  
      Creating a cache area
    2.  
      Displaying information about a cache area
    3. Enabling or disabling caching for a data object
      1.  
        Enabling or disabling caching for a file system
      2.  
        Enabling or disabling caching for a data volume
    4.  
      Adding a device to the cache area
    5.  
      Pausing caching from a volume to a cache area
    6.  
      Removing a device from the cache area
    7.  
      Destroying a cache area
    8.  
      Setting the attributes of the VxVM cache area
    9.  
      Setting or changing the caching mode for a VxFS cache area
    10.  
      Flushing dirty data from a writeback cache area
    11.  
      Tuning the writeback caching
    12. Viewing the SmartIO cache statistics
      1.  
        Viewing the detailed caching stats for a VxVM cache area
      2.  
        Viewing the detailed caching stats for a VxFS cache area
  4. Troubleshooting and error handling
    1. Support for a persistent or 'warm' VxVM cache
      1.  
        Primary volume failure with a stale cache could cause possible data corruption
      2.  
        Migrating a cache during HA failover is not supported
    2.  
      Cache area is lost after a disk failure (3158482)
    3.  
      Cache is not online after a reboot
    4.  
      Recovering the write-back cache after a node failure
  5. Appendix A. Command reference
    1.  
      SmartIO command reference

Tuning the writeback caching

When writeback caching is enabled, any data that is read from the disk is cached, unless the file is explicitly marked for "no caching" or if the cache is full. For writes, certain writes cause the data to be cached. You can load a file to speed up the application. Pinning a file in the cache ensures that the data does not get evicted. If some data is already cached, and that portion of the disk is overwritten, then SmartIO also writes the new data to the cache device to ensure that the cached data remains up to date.

If you are using a database template, SmartIO caches according to the template rules.

See About SmartIO caching for Oracle databases on VxFS file systems .

You can use the following tunable parameters to adjust the size of the cache and how long data is held in the cache.

Setting the maximum space used for dirty data per node

Setting the maximum retention time used for dirty data

Setting the maximum space used for dirty data per node

When writeback is enabled, you can configure how much of the cache is used for dirty data. The writeback_size attribute sets the maximum amount of cache area space that is used for writeback data for each file system. The maximum is set per node. By default, there is no maximum. If you configure a maximum, the value must be at least 512 MB.

For a cluster file system, SmartIO in writeback mode reflects, or mirrors, the cache data for each node to the other node's SSD cache. The actual disk space usage is twice the amount used for a standalone file system. The reflected data is not considered in the maximum size, however. For example, if the writeback_size is set to 512 MB, a cluster file system uses up to 512 MB on each node, for a total of 1024 MB.

Run the following command to configure the maximum. For a cluster file system, run the command on each node of the cluster to make the setting cluster wide. 

# sfcache set writeback_size=size

For example:

# sfcache set writeback_size=1g

Use the following command to view the current value:

# sfcache stat cachearea_name

See Viewing the SmartIO cache statistics .

Setting the maximum retention time used for dirty data

Dirty data is data in the cache that has not been flushed to the disk and so is out of sync with the data disk. The retention time determines how long the dirty data might remain unflushed. The default is 10 seconds.

For a cluster file system, run the command on each node of the cluster to make the setting cluster wide. 

# sfcache set writeback_interval=interval

For example:

# sfcache set writeback_interval=100

Use the following command to view the current value:

# sfcache stat cachearea_name

See Viewing the SmartIO cache statistics .