Tandberg Data NAS Hardware Viking FS-1500 - Manual (Page 103)

Tandberg Data Distributed File System
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7-13 Tandberg Viking Series Storage Server Administration Manual
7.5.5. Change How Target are Ordered in Referrals
In this task, you change settings that optimize how targets are ordered in
referrals. If you are not familiar with referrals, a referral is a list of targets that
a client computer receives from a domain controller or namespace server
when the user accesses a namespace root or folder with targets in the
namespace. The referral tells the client which servers host the associated
root target or folder target. So, for example, when a client navigates to
\\server_or_domain\Public, the client receives a root referral that contains a
list of root targets on the namespace servers. When the client then navigates
to the Tools folder, which has folder targets, the client receives a folder
referral that contains a list of folder targets that correspond to the Tools
folder.
When a client requests a referral, the Distributed File System service takes
into account the site of the client and the site of the target and provides a
referral with targets that are ordered according to the current referral
ordering method. By default, targets in a client’s site are listed first in a
referral in random order, followed by a list of targets outside of the client’s
site, sorted by lowest cost.
To fine-tune how targets outside of a client’s site are ordered, you can
change the ordering method for an entire namespace or for individual folders
with targets. Changing the ordering method is an important consideration in
namespaces whose targets span sites. For example, there might be
situations in which you want to prevent the client from accessing targets
outside of its own site. If so, you can configure the namespace root or folder
with targets so that clients receive referrals only for targets within their own
site.
To further optimize how targets are listed in referrals, you can set target
priority, which overrides the ordering method. For example, you can specify
that a target is always first or last in a referral, regardless of the client’s site,
or you can specify that a target is always first or last among the targets that
have the same connection cost. One common scenario for using target
priority is when you have a "hot standby" server that is considered the server
of last resort. In this scenario, you can specify that the standby server always
appears last in referrals, and clients will fail over to this server only if all the
other servers fail or become unavailable due to network outages.
In the following procedures, you verify the referral ordering method for the
namespace and choose target priority of a folder target.
To verify the referral ordering method for a namespace:
1. In the console tree of the DFS Management snap-in, right-click
\\server_or_domain\Public, and then click Properties.
2. On the Referrals tab, in Ordering method, verify that Lowest cost
is selected.
In the lowest cost ordering method, also called least expensive target
selection or site costing in previous documentation, targets in a referral are
ordered as follows: