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

Pre-compute hashes as desired:

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

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`

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

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                                                   -

Related information

Performance monitoring overview

ONTAP 9 Manuals ( CA08871-402 )

Pre-compute BranchCache hashes on specified paths

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