Installation manual

Configuring a Namespace
Configuring Windows Authentication (CIFS)
7-20 CLI Storage-Management Guide
Selecting a SAM-Reference Filer
CIFS clients, given sufficient permissions, can change the users and/or groups who
have access to a given file. For example, the owner of the “penicillin.xls” file can
possibly add “nurses” or “doctors” to the list of groups with write permission. The list
of groups in the network is traditionally provided by the Security Account
Management (SAM) database on the file’s server. The ARX does not provide an
internal SAM database; the namespace proxies all SAM queries to one of its CIFS
filers, chosen at random.
The filer used for SAM queries must contain a super set of all groups in all volumes,
or some of the groups will be missing from the list. If any volume has filers that
support Local Groups (as opposed to groups defined at the DC), you must configure
one filer with all groups. If none of the filers use local groups, you can skip to the next
section; the namespace can choose any of the filers as its SAM reference.
Use the gbl-ns
sam-reference command to identify the pre-configured filer:
sam-reference filer
where filer (1-64 characters) is the external filer’s name, as displayed in
show
external-filer
(see “Listing External Filers” on page 6-6).
For example, the following command sequence uses the “fs2” filer as a SAM
reference for all volumes in the medarcv namespace:
bstnA6k(gbl)# show external-filer
Name IP Address Description
------------------------ ------------- ----------------------------
das1 192.168.25.19 financial data (LINUX filer, rack 14)
fs2 192.168.25.27 bulk storage server (DAS, Table 3)
fs1 192.168.25.20 misc patient records (DAS, Table 3)
nasE1 192.168.25.51 NAS filer E1
According to the CIFS protocol, a CIFS-client application sends all of its SAM queries
through a special pseudo share, IPC$. Each CIFS namespace therefore has a separate
pseudo volume that it shares as IPC$. Since the queries come to this volume instead of
the file’s volume, the namespace software does not know the file’s volume. Therefore,
the namespace cannot intelligently choose an appropriate back-end filer as its SAM
reference.