PI72199: LOAD BALANCER CRASHES DUE TO CORRUPTED CONNECTION RECORDS

Fixes are available

APAR status

Closed as program error.

Error description

The crash was from corrupted connection records. The solution
was to change the locking in the garbage collection code to be
more inclusive.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  IBM WebSphere Application Server Edge       *
*                  Components Load Balancer for ipv4 and ipv6  *
*                  users                                       *
****************************************************************
* PROBLEM DESCRIPTION: Problems occur when using the high      *
*                      availability feature with multiple      *
*                      heartbeat pairs.                        *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The load balancer for ipv4 and ipv6 would replicate connection
record updates over every heartbeat. This would not only cause
extra network usage and processing but would also confuse the
connection state at the backup load balancer.

Problem conclusion

Code was modified to only replicate over a single heartbeat.
The heartbeat is checked for availability and the first
available heartbeat will be used for replication. This check
is performed for each replication so the replication could
move to a different heartbeat if one pair fails.

NOTE--Multiple heartbeats (or multiple reach targets) are
generally not a good configuration choice and the benefits and
drawback to such a configuration choice should be examined by
the administrator.

The load balancer priority is to forward traffic.
HighAvailiabity update run at a lower priority. Multiple
heartbeats and reach targets were added before the
release of high speed media (back when ethernet was limited to
10Mbps). At that time, if the network was heavily utiltized,
it was recommended to place an isolated subnet in between the
load balancer and define a separate heartbeat pair to prevent
false takeovers.

When multiple heartbeats (and reach targets) are used with
networks that do not have a capacity issue, they can cause
false takeover due to occasional missed packets which
introduces problems which would not exist with a single
heartbeat and single reach target and properly tuned timeout
values. The multiple heartbeats also consume more processing
time and network bandwidth than necessary and can delay the
primary purpose of the load balancers to forward traffic.

Fix included in:
    8.0.0.13
    8.5.5.12
    9.0.0.3

Temporary fix

Comments

APAR Information

APAR number
PI72199
Reported component name
WS EDGE LB IPV4
Reported component ID
5724H8812
Reported release
850
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-11-11
Closed date
2016-12-06
Last modified date
2016-12-06

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name
WS EDGE LB IPV4
Fixed component ID
5724H8812

Applicable component levels

R800 PSY
UP
R850 PSY
UP
R900 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.5","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
03 May 2022

Tips

PI72199: LOAD BALANCER CRASHES DUE TO CORRUPTED CONNECTION RECORDS

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R800 PSY

R850 PSY

R900 PSY

Document Information

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