Question & Answer
Question
After converting FTP from DNS/WLM to using sysplex distributor, the number of FTP PUTs per second appears to have signficantly decreased. What accounts for this apparent decrease in performance? What can be done to improve the performance of sysplex distributor?
Cause
By default, when using sysplex distributor, traffic from the distributing system to the target system uses the XCF links. For bulk transfers of data (especially FTP for transfers to the z/OS system), this results in very slow performance and increased CPU usage in the TCP/IP address space.
Answer
To speed up your FTP PUTs significantly when using sysplex distributor, you need to enable VIPAROUTE, which forces data transfer for FTP PUTs and other high-volume transfers to use OSA.
To enable VIPAROUTE, you need to specify the following in the VIPADYNAMIC section of the distributing stack's TCP/IP PROFILE:
- VIPAROUTE dynxcfip target_ipaddr
- where:
- dynxcfip is the IPv4 or IPv6 dynamic XCF address which uniquely identifies the target stack
See the section about VIPAROUTE in the IP Configuration Reference.
A VIPAROUTE statement (in the TCP/IP PROFILE) defines a route from a distributing stack or a backup distributing stack to a target stack. For example:
- VIPAROUTE DEFINE 10.1.1.5 10.50.10.1
The command NETSTAT VIPADYN /-v may be used to query the status of a dynamic VIPA, including the usage of VIPAROUTE; for example:
- MVS TCP/IP NETSTAT CS V1R9 TCPIP Name: TCPIPC 11:24:56
Dynamic VIPA:IpAddr/PrefixLen: 10.20.20.1/28
Status: Active Origin: VIPADefine DistStat: Dist/Dest
VIPA Route:
DestXCF: 10.1.1.5
TargetIp: 10.50.10.1
RtStatus: Active
Suggestion: For multiple LPARs on the same processor complex, consider defining a HiperSockets channel referenced by the IQDCHPID VTAM start option instead of a VIPAROUTE for those neighboring systems.
For more information, see the following Technotes:
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Document Information
Modified date:
15 June 2018
UID
swg21443866