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From Pid <...@pidster.com>
Subject Re: Tomcat memory requirements
Date Wed, 25 Jan 2012 23:01:50 GMT
On 25/01/2012 21:48, André Warnier wrote:
> Celso Magalhães Dantas Neto wrote:
>> Thanks everyone for the reply!
>>
>> My problem is not to argue how the application is consuming RAM, but to
>> show that 150MB is not too much memory. But for that I'd like to use
>> trusted information such as an article, or official info. The client
>> doesn't understand anything about technologies but has opened the Windows
>> Task Manager and saw that Tomcat is on top 3 in memory consumption. I
>> just
>> need to argue with him that 150MB is normal for a Java web app.
> 
> Celso,
> 
> your client, as you describe, knows nothing about technology or
> programming.
> And in this case, you are his expert.
> So if he knows nothing about the subject, but he does not accept the
> opinion of an expert, then the problem with your customer is bigger than
> about a few MB of RAM, and you are probably wasting your time.
> 
> As mentioned previously, the current cost of 150 MB of RAM is about US$
> 2.00.
> So why are you (both) wasting your time about this ?
> 
>>
>> I know that "normal" really depends on how your/my application
> 
> Exactly.  And nobody here knows your application, so nobody can tell you
> if 150 MB total is justified or not in this case.
> 
>> And yes I could start Tomcat with no app, and create a 1 CRUD
> application,
> but I would prefer to argue with some trusted article or official
> information.
> 
> This user list is the official Apache Tomcat project's users list, where
> Tomcat users from the whole world come to report problems and get advice
> and help.
> Many of the people here answering questions are members of the official
> Tomcat development team.  "MarkT" and "Pid" who answered before, /are/
> Tomcat developers.  How much more "official" do you need ?  Would some
> article on Google written by some unknown "expert" be better ?

I'm not actually a committer.  Just a mailing list lurker.


p

> And what these real experts have been telling you so far is that 150 MB
> of total memory shown in the Windows Task Manager, to run a Java JVM +
> Tomcat + an application is nothing that makes anybody wonder.  It looks
> perfectly "normal" for an application which does something useful, as we
> assume yours does.
> 
> 
> If it may help :
> 
> Following are some snapshots taken tonight on different production Linux
> systems, using the Linux "ps" utility, and sorting the processes by
> memory usage (more memory first).
> In each case, Tomcat runs basically the same simple application,
> consisting of a single servlet.
> As you can see, in most cases the top slots are occupied by java
> processes, with Tomcat among them.  And they all use much more than 150
> MB, despite the fact that all these systems are in Europe, and not doing
> very much right now.
> 
> 
> system # 1 :
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 26076 root      20   0 2386m 1.1g 9232 S    0  9.5  13:41.97 java
> 21875 tomcat55  20   0  698m 209m 9.8m S    0  1.7  54:02.10 jsvc
>  3862 star      20   0  418m 176m 8936 S    0  1.5  20:24.53 java
> 
> system # 2 :
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>  3053 tomcat55  20   0  320m 120m  12m S    0  6.0 462:27.13 jsvc
>  2916 star      20   0  353m  93m  11m S    0  4.7 376:03.26 java
> 21871 star      20   0  285m  79m 7648 S    0  4.0   2:49.06 java
> 
> system # 3 :
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 32116 www-data  20   0  717m 198m 6044 S    0  9.9   0:57.12 apache2
>  2958 tomcat55  20   0  456m 195m 9368 S    0  9.7   2120:42 java
> 32065 star      20   0  411m 142m 8996 S    0  7.1  12:34.17 java
> 32126 www-data  20   0  667m 138m 6056 S    0  6.9   0:37.78 apache2
> 
> system # 4 :
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>  3189 tomcat55  20   0  435m 296m  12m S 89.1 14.6   3049:49 jsvc
>  2744 root      20   0  3276 1348 1108 R  9.6  0.1   3658:11 vmware-guestd
> 17156 mira      20   0 40488  36m 2340 S  0.7  1.8 104:18.14 MiraLoader.pl
>  3234 star      20   0  214m  38m  11m S  0.3  1.9  46:10.17 java
> 
> The "RES" column is the "resident" memory, "VIRT" is the virtual memory.
> Compare that with the equivalent columns in your customer's Windows Task
> Manager.
> Note : the "jsvc" program is also java, running Tomcat.
> 
> Unfortunately, I do not have an equivalent system running Windows, but
> the figures would be much the same.
> 
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