Question & Answer
Question
How do you configure the CCRC WAN server to ensure optimal performance and high scalability for ClearCase Remote Client (CCRC) users in ClearCase Version 8.0 and later?
Answer
NOTE: These guidelines are derived from benchmark testing on servers with the minimum recommended hardware configuration. The testing entailed various commonly used ClearCase operations with an average transaction rate of 15 operations per hour per user. Start with the settings listed in this document and then adjust them based on your expected peak load.
Required System Resources
All platforms
- 8 GB of memory. If the CCRC WAN server is to host more than a single WAS profile (for example, ClearCase, ClearQuest, Requisite Pro), additional resources may be needed.
- Quad-core server CPUs provide a strong processor base.
- Services associated with the CCRC WAN server profile e.g.
IBM WebSphere Application Server V7.0 - ccrcprofile
must be set to allow the service to interact with the desktop system: - Increase the desktop heap size. See technote 1142584: ClearCase processes unexpectedly die on Microsoft Windows for instructions. This may not be needed for 64 bit machines.
- Set the Session size for scalability. The value depends on the peak concurrent usage.
Click Administrative Tools->Services
Right-click IBM WebSphere Application Server V7.0 - ccrcprofile
Click Log On
Select Allow service to interact with desktop
- Set Windows registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\SessionViewSize
to 96 or 192 based on expected peak load.Start with 96 and increase to 192 if out-of-memory errors are seen in CCRC WAN server profile's SystemOut.log e.g.
\Program Files\IBM\RationalSDLC\Common\ccrcprofile\logs\server1\SystemOut.log
during peak load.All UNIX/Linux
- The minimum requirement for swap space is twice the size of memory.
- Increase the maximum number of open file descriptors to handle the user load. Refer to operating system documentation for instructions on how to set this parameter. CAUTION: Setting this value too high increases size of the ClearCase back end (CCBE) and view server processes. Start with 16K file handles and then adjust as needed.
Solaris 10
- Disable the Nagle algorithm using the following command:
ndd -set /dev/tcp tcp_naglim_def 1
AIX
- Use an AIX Power 5, 6 or 7 host system.
- You must install the fix for APAR IZ55804 (AIX 5.3) or IZ52038 (AIX 6.1) to correct a problem that causes the portmapper daemon to hang. The fix is included in the 5300-11 technology level. To obtain the fix for AIX 6.1 refer to fixinfo112964: Fix pack information for: PORTMAPPER HANGS
- Set the following operating system parameters:
no -o tcp_nagle_limit=0
Most TCP implementations use the Nagle algorithm, where a TCP connection can have only one outstanding small segment that has not been acknowledged. This causes TCP to delay sending further packets until it receives an acknowledgement or until it can bundle more data and send a full-size segment.
no -o clean_partial_conns=1
Specifies whether synchronize-the-sequence-number (SYN) attacks are avoided. Enable this option to protect against network attacks.
no -o tcp_nodelayack=1
Enabling this parameter causes TCP to send immediate acknowledgement (ACK) packets to the sender. When the parameter
tcp_nodelayack
is off, TCP delays sending ACK packets by up to 200 ms. This allows the ACK packet to piggyback on a response and minimizes the system overhead. no -o rfc1323=1
Enables window scaling and time stamps as specified by RFC 1323 (TCP Extensions for High Performance). Window scaling allows the TCP window sizes (
tcp_recvspace
and tcp_sendspace
) to be larger than 64 KB (65,536) and is typically used for large maximum transmission unit (MTU) networks. If your ClearCase VOBs or CCRC WAN server are hosted on a Windows system, enable this parameter for optimal performance.
HP
- Increase the following tunable kernel parameter:
- Disable the Nagle algorithm:
maxfiles=4096
maxfiles_lim=8192
nfile=16384
ndd -set /dev/tcp tcp_naglim_def 1
Linux
- If PAM authentication is in use
- Increase max # files, edit /etc/security/limits.conf and set lines as follows:
cd /etc/pam.d
cp login clearcase
Edit file
clearcase
and comment out the line that contains the string securetty
(usually the first line).* soft nofile 16383
* hard nofile 16383
CCRC WAN server Parameters
CCRC WAN server configuration parameters are defined in
<CC_HOME>/config/ccrc/server.conf
e.g. c:\Program Files\IBM\RationalSDLC\Clearcase\config\ccrc\server.conf
For reference, use
<CC_HOME>/config/ccrc/server.conf.sample
- ccrcLoginSessionTimeout
- Description : Lifetime of an idle CCRC session. Session is terminated after timeout.
Value : Time interval in seconds
Default : 1800 seconds
Note : Timeout may be reduced for increased scalability. Recommended minimum is 900 seconds.
- ccrcPrimaryGroup
- Description : Primary Group to be effective for CCRC users.
Value : An operating system group that is valid on the server.
Default : NONE
Note : The effective primary group for all CCRC users using this server. This does not affect non-CCRC users.
- ccrcTempDir
- Description : Pathname to temporary directory used by the server.
Value : Pathname to a valid local directory with write access granted to all CCRC users.
Default : (Windows)C:\temp\ccrctemp (modifiable during install)
(UNIX/Linux)/var/tmp/ccrctemp (modifiable during install)
Note : This pathname can be also be set during installation. CCRC login fails if a user does not have write access to this directory.
- ccrcUploadLimit
- Description : Maximum size of file that may be uploaded to the server.
Value : Size in Kbytes.
Default : 15
Note : Set only to limit the size of files that can be uploaded to the server.
- ccrcUseViewHostPathForGlobalPath
- Description : Use global pathname to access view storage.
Value : true or false
Default : false
Note : This must be specified when view storage is not local to the server. It must be
true
for load balancing.- ccrcViewStorage
- Description : Path name to view storage.
CC_HOME\var\ccweb
if CC_HOME path does not contain embedded spaces
CC_HOME drive root:\ccweb
if CC_HOME path contains embedded spaces
Value : Valid local pathname if
ccrcUseViewHostPathForGlobalPath=false
. Valid global if ccrcUseViewHostPathForGlobalPath=true
.Default : On Windows,
/var/adm/rational/clearcase/ccweb
Note : This path should be outside the ClearCase installation location for ease of upgrade. Use this in conjunction with
ccrcUseViewHostPathForGlobalPath
.- ccrcVobLineTerminator
- Description : VOB line terminator for this server.
Value : LF or CR-LF
Default : None
Note : Set appropriately for a configuration of mixed platform types.
- ccrcClearQuestDatabaseMapFile
- Description : Pathname of the ClearCase/ClearQuest integration configuration file.
Value : Valid pathname of local file.
Default : None
Note : Applicable only to CCRC users.
- ccrcDownloadCompressionThreshold
- Description : Minimum file size to be compress prior to download to client.
Value : Kbytes
Default : 15
Note : Setting this value too low can adversely affect performance.
- ccrcSupportsParallelLoad
- Description : Flag to toggle enablement of parallel web view loads.
Value :
true
or false
Default :
true
Note : Refer to technote 1515393: About CCRC WAN Server parallel view loading for details. Modify this parameter in conjunction with
ccrcMaxRequestsPerSession, ccrcMaxRequestsOverall and ccrcMaxSessionsOverall
. See Note below. - ccrcMaxRequestsPerSession
- Description : Maximum number of simultaneously active requests per session.
Value : > 0
Default : 10
Note : Modify this parameter in conjunction with
ccrcSupportsParallelLoad, ccrcMaxRequestsOverall , ccrcMaxSessionsOverall and ccrcSupportsParallelLoad
. See Note below.- ccrcMaxRequestsOverall
- Description : System-wide limit of simultaneously active requests.
Value : > 0
Default : 300
Note : Modify this parameter in conjunction with
ccrcSupportsParallelLoad, ccrcMaxRequestsPerSession and ccrcMaxSessionsOverall
. See Note below.- ccrcMaxSessionsOverall
- Description : System-wide limit on number of simultaneously active sessions.
Value : > 0
Default : 200
Note : Modify this parameter in conjunction with
ccrcSupportsParallelLoad, ccrcMaxRequestsPerSession and ccrcMaxRequestsOverall
. See Note below.NOTE:
ccrcMaxRequestsPerSession
*ccrcMaxSessionsOverall
= the maximum number of active CCBE (ClearCase Back End) processes expected whenccrcMaxSessionsOverall
number of CCRC sessions are active with peak activity. Each instance of CCBE processes only one request at a time.
ccrcMaxRequestsOverall
should NOT be set to(ccrcMaxRequestsPerSession * ccrcRequestsPerSession)
.ccrcMaxRequestOverall
should be set to the maximum number of CCBE processes (in addition to other processes on the server machines e.g. view servers, etc) that are sustainable on the system (based on system resources).
- Refer to technote 1515393 for configuration guidelines for Parallel Web View load.
- Set WAS thread pool max limits to be >=
maxRequestsOverall
.
WAS Configuration parameters for the CCRC WAN server Profile
Use the WAS console (http://server:port/ibm/console) to make changes. The port for the console is listed in
<profile-home>/logs/server1/AboutThisProfile.txt
, where <profile-home> is the CCRC profile's home directory. See "Commonly Used Commands" below.The default values are applied to the default CCRC WAN server Profile,
ccrcprofile
, if a new profile is created during install.If the CCRC WAN server is deployed in an existing profile, the defaults must be applied after careful consideration if the profile is shared with other applications.
To apply the default values to the profile hosting the CCRC WAN server :
- In a command window, change directory to :
- Run the following command :
- On Windows, <ccase-home-dir>\var\web, where <ccase-home-dir> is the location of where ClearCase is installed e.g. C:|Program Files\IBM\RationalSDLC\Clearcase
On UNIX/Linux, /opt/rational/clearcase/web
On Windows,
<profile-home>\bin\wsadmin.bat -c "source ccrcAdminUtils.jacl" -c "setCCRCRecommendedDefaults"
On UNIX/Linux, profile-home/bin/wsadmin.sh -c "source ccrcAdminUtils.jacl" -c "setCCRCRecommendedDefaults"
where <profile-home> is the CCRC profile's home directory. See "Commonly Used Commands" below.
Servers->Server Types>WebSphere Application Server>server1>Web container>Custom property
com.ibm.ws.webcontainer.channelwriteType
=sync
Servers>Server Types-WebSphere Application Server>server1>Web container transport chains>WSInboundDefault>Http inbound channel
Write timeout=300 seconds
Persistent timeout=120 seconds
Servers>Server Types>WebSphere Application Server>server1>Process definition>Java Virtual Machine
Initial heap size=1024 MB
Maximum heap size=1024MB
Servers>Server Types>WebSphere Application Server>server1>Thread Pools
Web Container=300
Default=300
Environment>WebSphere Variables>
AIX_THREAD_SCOPE=S
Troubleshooting>Logging and Tracing>server1>Diagnostic trace service
Maximum File Size=20MB
Maximum number of Historical files=20
Commonly Used Commands
This section contains commonly used command referred to in this document.
Locating the WAS profile home directory (profile-home)
- In a command window, enter the command :
On Windows,
<was-home>\bin\manageprofiles.bat -getPath -profileName <profile name>
On UNIX/Linux, <was-home>\bin\manageprofiles.sh -getPath -profileName <profile name>
where <was-home> is the WebSphere installation location.
Listing WAS profiles on the system
- In a command window, enter the command :
On Windows,
<was-home>\bin\manageprofiles.bat -listProfiles
On UNIX/Linux, <was-home>\bin\manageprofiles.sh -listProfiles
where <was-home> is the WebSphere installation location.
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Document Information
Modified date:
01 August 2018
UID
swg21514940