Configuring file caching options

Server and Cluster Administration Guide for Hitachi NAS Platform

Version
15.1.x
Audience
anonymous
Part Number
MK-92HNAS010-35
  1. Navigate to Home > Storage Management > Read Cache Options to display the Read Cache Options page.


    Field/Item Description
    Before caching, a file must remain unmodified for Specifies how long a file must be unchanged before it is eligible for caching.

    The default minimum stable time is 10 minutes.

    This does not indicate how long since the file has been accessed, only that the file may not have been changed within this period. You can specify the time in seconds, minutes, hours, or days.

    Do not cache files larger than Limits the maximum size of a file eligible for caching.

    The default maximum size is 512 MiB. You can specify the maximum size of a file in Bytes, KiB, MiB, GiB, TiB, PiB, or EiB.

    Caching large files might limit the number of files that the read cache can contain. If necessary, you can expand the read cache as described in the File Services Administration Guide.

    Files may be removed from cache if not accessed for Which indicates the amount of time that a file will remain in the read cache without being accessed before it is designated as inactive. Inactive files are eligible for removal from the cache, and are deleted on an "as space is needed" basis, with the oldest inactive files being deleted until there is enough space for a new file to be added to the read cache.

    The default duration is 15 minutes. You can specify the amount of time in seconds, minutes, hours, or days.

    Once removed, a file cannot be cached again for at least Specifies the minimum time that must elapse before a file is re-evaluated for read caching after:
    • Having been read cached, and then having been flushed from the read cache for any reason.
    • Being evaluated for read caching, and not being cached for some reason. Reasons for not caching a file may include file size, too recent modification, or insufficient space available in the read cache.

    The default retry time is 30 minutes. You can specify the amount of time that must elapse before a file can be cached again in seconds, minutes, hours, or days.

    apply Click to save the values specified for the options on this page.
    Reset Values to Default Click to reset the values on this page to their defaults.
    Note: This link does not reset the active file set, which must be done through the CLI (Command Line Interface).
    Read Cache Statistics Click this shortcut to go to the Read Cache Statistics page.
  2. Set the options, and click apply to apply changes, or Reset Values to Default to restore defaults.
    Note: You can prohibit read caching of files from a particular file system when the link to that file system is added to the CNS tree.