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Veritas Access Administrator's Guide

Last Published: 2021-04-15

Product(s): Appliances (Version Not Specified)

Platform: 3340

Customizing the caching behavior

By default, SmartIO caches the file data based on the workload. SmartIO loads portions of files into the cache based on I/O access. When the cache area fills, data may be evicted to make room for caching new data. SmartIO uses criteria such as frequency of access to evict data. While the data is in the cache, the subsequent I/Os to that file data are satisfied from the cache. If the data is evicted, any subsequent I/O request is served from the primary storage. SmartIO may then cache the data again.

To maximize the use of the cache, you can customize the caching behavior to control when files are loaded or evicted from the cache. You can customize the caching behavior, using the following operations:

The load operation preloads files into the cache before the I/O accesses the files. The files are already in the cache so that the I/Os return more quickly. The files are loaded asynchronously in the background.
The pin operation prevents the files from being evicted from the cache. You can pin commonly used files so that SmartIO does not evict the files and later need to cache the files again. A pinned file is kept in the cache indefinitely, until it is deleted or explicitly unpinned.
The unpin operation removes files from the pinned state. The unpin operation does not cause the file to be immediately evicted. SmartIO considers the file for eviction in the same way as any other file, when space is required in the cache.

For each of these operations, you can specify files individually, or specify a directory name to affect all of the files in a directory.

To load a file or directory

To load a file or directory to the cache, specify the file name or the directory name to the following command.
```
SmartIO> file load  {file|dir}
```
Where:
file is the full path name of the file to be loaded.
dir is the directory name. If you specify a directory name, all of the files in the directory are loaded.

To pin a file or directory

To pin a file or directory to the cache, specify the file name or directory name to the following command.
```
SmartIO> file pin {file|dir}
```
Where:
file is the full path name of the file to be pinned.
dir is the directory name. If you specify a directory name, all of the files in the directory are pinned.

To unpin a file or directory

To unpin a file or directory to the cache, specify the file name to the following command.
```
SmartIO> file unpin {file|dir}
```
Where:
file is the full path name of the file to be unpinned.
dir is the directory name. If you specify a directory name, all of the files in the directory are unpinned.