IBM E16RMLL-I - Tivoli Storage Manager, Руководство по внедрению

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Chapter 15. Performance considerations
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that the server must handle. If you need 10 concurrent nodes to perform backup
operations and each of them has a multi-threading capability (resource
utilization) of 4, then you must set maxsession to at least 40 (10 x 4).
MAXSCHEDSESSIONS
The MAXSCHEDSESSIONS parameter specifies the number of sessions that
the server can use for processing scheduled operations. It is specified as a
percentage of the total number of server sessions available (the MAXSESSION
parameter). You should set this to less than 100, otherwise it could lead to a
situation where all the available sessions are being used for running client
scheduled backups and a critical restore cannot run because there are no spare
session slots.
Use the
query status
command to display the current MAXSCHEDSESSIONS
value, and change it to another value with the
set maxschedsessions
command.
TCPWINDOWSIZE
This option specifies the size of the TCP sliding window in kilobytes. The
TCPWINDOWSIZE option overrides the operating system's TCP send and
receive spaces. In AIX, for instance, these parameters are named
tcp_sendspace and tcp_recvspace. The TCPWINDOWSIZE option specifies the
size of the TCP sliding window for all clients and all but MVS servers. A larger
window size can improve communication performance, but uses more memory.
It enables multiple frames to be sent before an acknowledgment is obtained from
the receiver. If long transmission delays are being observed, increasing the
TCPWINDOWSIZE may improve throughput.
The size of the TCP/IP buffer is used when sending or receiving data. The
window size used in a session is the smaller of the server and client window
sizes. Larger window sizes use additional memory but may improve
performance.
The general recommendation is to set TCPWINDOWSIZE to 64 (except
Windows, which is 63). Clients now default to 63. In an SP2 environment with a
high-speed switch set the TCPWINDOWSIZE to a value between 128–640, and
when using Gigabit Ethernet with Jumbo Frames – 9000 MTU set the
TCPWINDOWSIZE to 128.
Tip: On AIX, the network option
rfc1323
must be set on to have TCPWindow
sizes larger than 64K-1.