|
RESOURCEUTILIZATION
Resourceutilization is a client option used to regulate the level of resources (i.e. number
of concurrent sessions) the TSM client and server can use during processing. Multiple
sessions are created automatically through a single invocation of a TSM backup/restore
or archive/retrieve command.
Even though the multi-session function is transparent to the end user and is started
automatically, there are some parameters which enable the user to customize the function.
There is a way to influence the multi-session function with the option
RESOURCEUTILIZATION. This option increases or decreases the ability of the Tivoli
Storage Manager client to create multiple sessions. For Backup or Archive the value of
RESOURCEUTILIZATION does not directly specify the number of sessions created by
the client. However, this setting specifies the level of resources the Tivoli
StorageManager server and client can use during backup or archive processing. The
higher the value, the more sessions the client can start if it deems necessary. The range
for the parameter is from 1 to 10. When the option is not set, which is the default, then
only two sessions are created to the server.
Default resourceutilization level allows up to two sessions with the server, one for
querying the server and one for sending file data. Resourceutilization=5 permits up to
four sessions (two for queries and two for sending data), while resourceutilization=10
permits up to eight sessions (four for queries and four for sending data) with the server.
The relationship between Resourseutilization and the maximum number of sessions
created is part of an internalized algorithm and, as such, is subject to change. This table
lists the relationships between Resourceutilization values and the maximum sessions
created. Producer sessions scan the client system for eligible files. The remaining
sessions are consumer sessions and are used for data transfer. The threshold value affects
how quickly new sessions are created.
Table 2. Resource Utilization Settings
Back
up
throu
ghpu
t
impr
ove
ment
s that
can
be
achie
ved
by
increasing the Resourceutilization level will vary from client node to client node. Factors
that affect throughputs of multiple sessions include the configuration of the client storage
subsystem (i.e. layout of file systems on physical disks), the client's ability to drive
multiple sessions (sufficient CPU, memory), the server's ability to handle multiple client
sessions (CPU, memory, number of storage pool volumes), and sufficient bandwidth in
the network to handle the increased traffic.
The MAXSESSIONS parameter controls the maximum number of simultaneous client
sessions with the Tivoli Storage Manager server. The total number of parallel sessions for
a client is counted for the maximum number of sessions allowed with the server. For this
reason, you need to consider whether to increase the value of the MAXSESSIONS
parameter in the server option file.
When using the Resourceutilization option to enable multiple client/server sessions for
backup direct to tape, the client node maximum mount points allowed parameter,
MAXNUMMP, must also be updated at the server (using the Update Node command).
If the TSM client has a filesystem spread across multiple disks (RAID 0 or RAID 5), or
multiple large filesystems, we recommend setting the TSM client option
Resourceutilization to a value of 5 or 10. This will enable multiple sessions with the
server during backup or archive, and can result in substantial throughput improvements in
some cases. It is not likely to improve incremental backup of a single large filesystem
with a small percentage of changed data. If backup is direct to tape, then the client node
maximum mount points allowed parameter, MAXNUMMP, must also be updated at the
server using the update node command.
When a restore is requested, the default is to use a maximum of two sessions, based on
how many tapes the requested data is stored on, how many tape drives are available, and
the maximum number of mount points allowed for the node.
RU Value Max # of Sessions Unique # of Producer Sessions Threshold (secs)
1 1 0 45
2 2 1 45
3 3 1 45
4 3 1 30
5 4 2 30
6 4 2 20
7 5 2 20
8 6 2 20
9 7 3 20
10 8 4 10
default (0) 2 1 30
The default value for the RESOURceutilization parameter is one (1) and the maximum
value is ten (10).
For example, if the data to be restored are on five different tape volumes, and the
maximum number of mount points is five for the node requesting the restore, and
RESOURceutilization is set to three, then three sessions will be used for the restore. If
the RESOURceutilization setting is increased to five, then five sessions will be used for
the restore. There is a one-to-one (1:1) relationship to the number of restore sessions
allowed and the RESOURceutilization setting.
Resourceutilization Values
• Values >2 allowed only when connecting to a >3.7 server
• Non-root UNIX limited to 1 session
Recommendation
RESOURceutilization 1 workstations, 5 small server, 10 large server
|
