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IBM's Tivoli Storage Manager (TSM) client software is very slow due to repeated JAR file downloads when the server does not provide HTTP header 'last-modified'. With TSM there is a native client and a web client provided. The web client is a Java applet, which consists of only one jar file "dsm.jar". This applet is having the problem. 1. behavior ----------- I used TSM web client Version 5, Release 4, Level 1.0. 1.1 JRE 1.4.2 or JRE 1.5.0 --------------------------- Using the TSM web client on JRE 1.4.2_16 or on 1.5.0_15 shows repeated downloads of its jar file of "dsm.jar". For only launching the applet, 16, resp, 17 attempts were counted, resulting in a message about not caching the file each time: network: Connecting http://<tsm-srv>:1581/dsm.jar with proxy=HTTP @ <proxy-server>:8080 network: Connecting http://<tsm-srv>:1581/dsm.jar with cookie "SUN_ID=<wiped>:52987908580279" basic: Last modified time and/or expiration value is not available. Jar file will not be cached. 1.2 JRE 1.6.0 -------------- On JRE 1.6.0 the file "dsm.jar" is reported to be downloaded 18 times: network: Connecting http://<tsm-srv>:1581/dsm.jar with proxy=HTTP @ <proxy-server>:8080 with the following message associated: network: Cache entry not found [url: http://<tsm-srv>:1581/dsm.jar, version: null] 1.3 Performance ---------------- It was measured the time from invoking a GUI function until the GUI fully responded by entirely having popped up the appropriate window. The cache was switched off by: 1.5.0: Java (TM) Control Panel -> General -> Settings -> View Applets -> Options -> uncheck "Enable Caching" 1.6.0: Java Control Panel -> General -> Settings uncheck "Keep temporary files on my computer" 1.5.0_15 / time [sec] w/o cache w/ cache Launch of applet 10 20 File->Connection Information 1 2 Restore button 4 20 1.6.0_06 / time [sec] w/o cache w/ cache Launch of applet 12 146 (= 2:26 min) File->Connection Information 2 7 Restore button 3 404 (= 6:44 min) So, there is factor 7 (146/20) for only launching the applet, and factor 20 (404/20) for popping up a dialogue window for one of the applet's basic functions. 1.4 TSM Web Server ------------------- 1.4.1 HTTP/1.0 -------------- The TSM Web Server appears to be sending HTTP/1.0: % telnet <tsm-srv> 1581 Trying [wiped]... Connected to <tsm-srv>. Escape character is '^]'. HEAD / HTTP/1.1 HTTP/1.0 501 Not Implemented Server: TSM_HTTP/0.1 Content-type: text/html [ ... ] 1.4.2 no 'last-modified' header ------------------------------- % wget -S --server-response http://<tsm-srv>:1581/dsm.jar --15:23:22-- http://<tsm-srv>:1581/dsm.jar => `dsm.jar' Resolving <proxy-server>... [wiped], [wiped] Connecting to <proxy-server>|[wiped]|:8080... connected. Proxy request sent, awaiting response... HTTP/1.1 200 OK Date: Mon, 14 Apr 2008 13:23:22 GMT Content-length: 2102631 Server: TSM_HTTP/0.1 Via: 1.0 proxy-proxy Proxy-agent: Sun-Java-System-Web-Proxy-Server/4.0 Connection: close Length: 2,102,631 (2.0M) 100%[======================================================================>] 2,102,631 355.64K/s ETA 00:00 15:23:29 (323.94 KB/s) - `dsm.jar' saved [2102631/2102631] % 1.5 dependency on http proxy server ----------------------------------- It was not clear from the description so far, that the issue is not only dependent on the JRE but also on the http proxy server. I used three different http proxy servers and compared these against the use of no proxy server. I measured TSM applet download time in seconds from URL http://10.16.50.171:1581/ depending on JRE and depending on http proxy server. IE 6 mit Classic Plug-in auf JRE 1.4.2_08 ----------------------------------------- proxy / time [sec] cache enabled cache disabled no proxy 34-34 34-34 uk 37-38 35-35 central 44-61 41-42 sfbay 59-59 45-45 IE 6 mit Classic Plug-in auf JRE 1.5.0_17 ----------------------------------------- proxy / time [sec] cache enabled cache disabled no proxy 35-36 33-36 uk 39-40 36-37 central 55-55 41-43 sfbay 60-63 45-46 IE 6 mit Classic Plug-in auf JRE 1.6.0_07 ----------------------------------------- proxy / time [sec] cache enabled cache disabled no proxy 38-40 33-35 uk 61-65 36-36 uk 61-62 36-36 central 186-187 42-42 sfbay 214-215 45-45 We can see the following: - The use of a http proxy server has an effect on start-up time regardless if cache was enabled or not. - The effect is more visible when cache is enabled compared to cache disabled. - The effect of use of a http proxy server is very prominent, when using JRE 1.6 and having cache enabled.
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