Pre-compute BranchCache hashes on specified paths

Contributors

You can configure the BranchCache service to pre-compute hashes for a single file, for a directory, or for all files in a directory structure. This can be helpful if you want to compute hashes on data in a BranchCache-enabled share during off, non-peak hours.

About this task

If you want to collect a data sample before you display hash statistics, you must use the statistics start and optional statistics stop commands.

  • You must specify the storage virtual machine (SVM) and path on which you want to pre-compute hashes.

  • You must also specify whether you want hashes computed recursively.

  • If you want hashes computed recursively, the BranchCache service traverses the entire directory tree under the specified path, and computes hashes for each eligible object.

Steps
  1. Pre-compute hashes as desired:

    If you want to pre-compute hashes on…​ Enter the command…​

    A single file or directory

    vserver cifs branchcache hash-create -vserver vserver_name -path path -recurse false

    Recursively on all files in a directory structure

    vserver cifs branchcache hash-create -vserver vserver_name -path absolute_path -recurse true

  2. Verify that hashes are being computed by using the statistics command:

    1. Display statistics for the hashd object on the desired SVM instance: statistics show -object hashd -instance vserver_name

    2. Verify that the number of hashes created is increasing by repeating the command.

Examples

The following example creates hashes on the path /data and on all contained files and subdirectories on SVM vs1:

cluster1::> vserver cifs branchcache hash-create -vserver vs1 -path /data -recurse true

cluster1::> statistics show -object hashd -instance vs1
Object: hashd
Instance: vs1
Start-time: 9/6/2012 19:09:54
End-time: 9/6/2012 19:11:15
Cluster: cluster1

    Counter                                                     Value
    -------------------------------- --------------------------------
    branchcache_hash_created                                       85
    branchcache_hash_files_replaced                                 0
    branchcache_hash_rejected                                       0
    branchcache_hash_store_bytes                                    0
    branchcache_hash_store_size                                     0
    instance_name                                                vs1
    node_name                                                  node1
    node_uuid
                                11111111-1111-1111-1111-111111111111
    process_name                                                   -

cluster1::> statistics show -object hashd -instance vs1
Object: hashd
Instance: vs1
Start-time: 9/6/2012 19:09:54
End-time: 9/6/2012 19:11:15
Cluster: cluster1

    Counter                                                     Value
    -------------------------------- --------------------------------
    branchcache_hash_created                                       92
    branchcache_hash_files_replaced                                 0
    branchcache_hash_rejected                                       0
    branchcache_hash_store_bytes                                    0
    branchcache_hash_store_size                                     0
    instance_name                                                vs1
    node_name                                                  node1
    node_uuid
                                11111111-1111-1111-1111-111111111111
    process_name                                                   -

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