# Servoy memory usage question **URL:** \ **Category:** Classic Servoy\ **Created:** [November 12, 2012, 7:03am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728 "2012-11-12T07:03:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 12, 2012, 7:03am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/1 "2012-11-12T07:03:07Z")
Hi, I have a Debian linux server which we use only for Servoy. It has two instances of servoy, one in 32 bit mode and one in 64 bit mode (5.2.14), MySQL and Terracotta. All users are webclients and there are a couple of headless clients running. (Why all on the one box… it’s a long story). It seems to require a lot more RAM than I’d expect. Can anyone tell me what’s normally expected for RAM usage. The configuration is Servoy64 with -Xmx3g -Xms1g -XX:MaxPermSize=256m Servoy32 with -Xmx512m -Xms512m -XX:MaxPermSize=256m Terracotta with default settings -Xms512m -Xmx512m MySQL, standard install. some monitors which use almost nothing, eg jstatd With 8GB of RAM it would run out of memory and crash from time to time. This seems odd, as we only allocate 4Gb for Servoy and TC. Increasing the RAM to 12GB stopped the crashes, but I find that even with light webclient load (5-10 WCs) the RAM used slowly goes up to around 10-11GB, seen in this graph, even though the servoy-admin page reports Heap memory used to be low. The first part of the graph shows typical usage. I restarted the cluster around 7am on Sunday, then it slowly came back up to similar levels. On a busy day this would peak very quickly. [attachment=0]page7image2952-1.png[/attachment] You can see that it uses 8-10GB of RAM, with 2-5GB of cache and very little free RAM. In the servoy admin panel, reported heap memory usually shows plenty of free RAM e.g. System Information Heap memory: allocated=1004928K, used=349316K, max=2796224K None Heap memory: allocated=99520K, used=81911K, max=311296K htop snippet just after a restart shows Servoy taking most of the RAM ```auto PID USER PRI NI VIRT RES SHR S CPU% MEM% TIME+ Command 25676 servoy 20 0 5123M 2489M 17148 S 116. 20.7 11:24.35 /bin/sh /home/servoy/terracotta/platform/bin/dso-java.sh -Dtc.config= 22501 servoy 20 0 2857M 2464M 5168 S 72.0 20.5 11h26:03 /usr/lib/jvm/ia32-java-6-sun/jre/bin/java -Xbootclasspath/p:/home/ser 22474 servoy 20 0 1277M 671M 5556 S 46.0 5.6 13h01:18 /usr/lib/jvm/java-6-sun/jre/bin/java -server -XX:MaxDirectMemorySize= 1599 mysql 20 0 327M 84012 4184 S 7.0 0.7 25h12:30 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql 1418 servoy 20 0 3301M 32932 5560 S 0.0 0.3 17:55.79 /usr/bin/jstatd -p 8082 -J-Djava.security.policy=/home/servoy/jstatd/ 4425 servoy 20 0 24968 7780 1560 S 0.0 0.1 0:00.31 -bash ``` What things should I be looking at to improve memory management? ![page7image2952-1.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/e/e39db45d2ff0d04077df65bb74c187b6f7a62129.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 12, 2012, 9:52am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/2 "2012-11-12T09:52:36Z")
I would like to see the full commands listed by htop. To see which is which and that the memory settings are listed in there correctly. I see a dso-java.sh which should be one of the Servoy Servers (why isn’t the other one a ‘dso-java’ as well?). Then there is one 32 bit java command, and then one java command. You said that htop was ran right after restarting the cluster. I’m looking to see that on the graph (\>9 GB virtual (reserved memory for the processes) and \>5.5 GB actual physical memory in use)… what do “used” and “cache” memory mean in that graph tool? I would think that ‘cache’ refers to the file cache used by the OS - that is not relevant here as it can be shrunk/freed up for application use when needed. And ‘used’ refers either to the virtual memory or actual physical memory allocated as reported by htop I guess… If it’s the ‘RES’ memory then I see it reaching 5.5 GB after ~2h 30m from the restart on the graph. Or was htop ran just before the restart, not after? A combination of jvisualvm/jstatd (or jvisualvm directly if you have UI on the server) can show the memory usage of the java application excluding the internal JVM memory usage. Anyway, you will never get the same values reported for the OS java process and jvisualvm/Servoy admin pages (which are limited by the -X… arguments) because the latter only reports heap/permgen space which is relevant only for the java application that executes and gives no insight into the internal memory usage of the JVM itself (which added would give the COMMIT size of the entire java process not the WORKING SET size which is usually shown by default (talking now in Windows terms, but its similar on linux with VIRT and RES) - for example you might even see lower OS reported WORKING SET memory then what jvisualvm reports as heap size + permgen size). For the things you can configure with the -X… parameters you should only look in jvisualvm (or similar) - that shows info about the application’s memory requirements, but if you are interested in how much RAM the whole process uses from the OS, that will be what jvisualvm reports + some amount used internally by the JVM which is decided by the JVM itself. See [http://www.coderanch.com/t/203149/Perfo … anager-JVM](http://www.coderanch.com/t/203149/Performance/java/Gap-between-task-manager-JVM) To come back to the initial question. I would like to see the commands as I stated in the beginning + when using the most memory, at that moment: - the values reported by htop - the values reported for heap/non-heap (used/size) by jvisualvm after triggering a garbage-collection cycle for each of the 3 processes (terracotta/app. server 1/app. server 2) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 12, 2012, 10:40am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/3 "2012-11-12T10:40:40Z")
I did a small test with 2 clustered servers and the servoy\_sample\_crm solution a while ago to see the memory use trend when starting new clients. It’s not exactly a real deployment, it’s just an example, but it’s the same idea. I thought you might be interested. Heap usage monitored running Terracotta 3.7.0 with 2 clustered 6.1.2 Servoy Application Servers, under Windows 7 64 bit with Java 1.6.0\_30 64 bit (heap sizes are truncated to MB, and sampled after requesting garbage collection with jvisualvm): - after starting the Terracotta server (let’s call it TS) and the 2 clustered Servoy Application Servers (let’s call them SAS1 and SAS2) =\> TS 13 MB, SAS1 40 MB, SAS2 40 MB - after starting a “servoy\_sample\_crm” web client on SAS1 (and using it a bit) =\> TS 13 MB, SAS1 47 MB, SAS2 40 MB - after starting a “servoy\_sample\_crm” web client on SAS2 (and using it a bit) =\> TS 13 MB, SAS1 47 MB, SAS2 47 MB - after starting another “servoy\_sample\_crm” web client on SAS1 (and using it a bit) =\> TS 13 MB, SAS1 54 MB, SAS2 47 MB Conclusion: When running clustered with Terracotta and Servoy, the bulk (almost all) of the heap memory used for a client is reserved only on the application server that serves it. The shared cluster heap’s size - which is kept entirely in the terracotta server process, and parts of it are duplicated/available to particular servoy application server processes as needed - is very small in comparison. It does grow with each new client that connects to any server in the cluster, but the shared info about each client is minimal. So the Terracotta Server allocated heap increased but very little, while the Servoy Application Server allocated heap sizes increased with about 7 MB per client. Of course, for larger solutions these increments will grow, but the shared heap allocation will continue to be very small in comparison to the heap reserved on the Servoy Application Server servicing the client. ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 12, 2012, 9:39pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/4 "2012-11-12T21:39:22Z")
Hi Andrei, Thanks for the detailed reply. I’ve attached a screenshot of htop, just after restarting the cluster from the command line, and the Java VisualVM graphs. Perform GC isn’t available from within VisualVM for this remote host. Please note that we’ve modified the startup scripts to run under Daemontools. I’d manually restarted one of the servoy instances yesterday via the admin panel, which would explain why there was only 1 ‘dso-java’ start-terracotta-server.sh ```auto #! /bin/bash # Start a local Terracotta server. # Use this instead of the script provided as part of Terracotta to allow it to run under Daemontools. exec /usr/lib/jvm/java-6-sun/jre/bin/java -server -XX:MaxDirectMemorySize=9223372036854775807 -Xms1g -Xmx1g -XX:ErrorFile=/home/servoy/terracotta/java_crash_logs/hs_err_pid%p.log -XX:+HeapDumpOnOutOfMemoryError -Dcom.sun.management.jmxremote -Dtc.install-root=/home/servoy/terracotta/ -Dtc.config=/home/servoy/terracotta/tc-config.xml -Dsun.rmi.dgc.server.gcInterval=31536000 -cp /home/servoy/terracotta/lib/tc.jar com.tc.server.TCServerMain ``` start\_servoy\_clustered\_32.sh ```auto #!/bin/sh # Start a clustered Servoy instance using 32-bit java. # Use this instead of the script provided as part of Terracotta to allow it to run under Daemontools. export JAVA_HOME="/usr/lib/jvm/ia32-java-6-sun/jre" exec "/home/servoy/terracotta/platform/bin/dso-java.sh" -Dtc.config=/home/servoy/terracotta/tc-config.xml -Dtc.node-name=Servoy32 -Djava.awt.headless=true -Xmx512m -Xms512m -XX:MaxPermSize=256m -XX:ErrorFile=/home/servoy/terracotta/java_crash_logs/hs_err_pid%p.log -classpath .:lib/ohj-jewt.jar:lib/MRJAdapter.jar:lib/compat141.jar:lib/commons-codec.jar:lib/commons-httpclient.jar:lib/activation.jar:lib/antlr.jar:lib/commons-collections.jar:lib/commons-dbcp.jar:lib/commons-fileupload-1.2.1.jar:lib/commons-io-1.4.jar:lib/commons-logging.jar:lib/commons-pool.jar:lib/dom4j.jar:lib/help.jar:lib/jabsorb.jar:lib/hibernate3.jar:lib/j2db.jar:lib/j2dbdev.jar:lib/jdbc2_0-stdext.jar:lib/jmx.jar:lib/jndi.jar:lib/js.jar:lib/jta.jar:lib/BrowserLauncher2.jar:lib/jug.jar:lib/log4j.jar:lib/mail.jar:lib/ohj-jewt.jar:lib/oracle_ice.jar:lib/server-bootstrap.jar:lib/servlet-api.jar:lib/wicket-extentions.jar:lib/wicket.jar:lib/wicket-calendar.jar:lib/slf4j-api.jar:lib/slf4j-log4j.jar:lib/joda-time.jar:lib/rmitnl.jar:lib/networktnl.jar com.servoy.j2db.server.ApplicationServer "$@" 1>> server.log 2>> server.log ``` start\_servoy\_clustered\_64.sh ```auto #!/bin/sh # Start a clustered Servoy instance using 64-bit java. # Use this instead of the script provided as part of Terracotta to allow it to run under Daemontools. export JAVA_HOME="/usr/lib/jvm/java-6-sun/jre" exec "/home/servoy/terracotta/platform/bin/dso-java.sh" -Dtc.config=/home/servoy/terracotta/tc-config.xml -Dtc.node-name=Servoy64 -Djava.awt.headless=true -Xmx3g -Xms1g -XX:MaxPermSize=256m -XX:ErrorFile=/home/servoy/terracotta/java_crash_logs/Servoy64/hs_err_pid%p.log -classpath .:lib/ohj-jewt.jar:lib/MRJAdapter.jar:lib/compat141.jar:lib/commons-codec.jar:lib/commons-httpclient.jar:lib/activation.jar:lib/antlr.jar:lib/commons-collections.jar:lib/commons-dbcp.jar:lib/commons-fileupload-1.2.1.jar:lib/commons-io-1.4.jar:lib/commons-logging.jar:lib/commons-pool.jar:lib/dom4j.jar:lib/help.jar:lib/jabsorb.jar:lib/hibernate3.jar:lib/j2db.jar:lib/j2dbdev.jar:lib/jdbc2_0-stdext.jar:lib/jmx.jar:lib/jndi.jar:lib/js.jar:lib/jta.jar:lib/BrowserLauncher2.jar:lib/jug.jar:lib/log4j.jar:lib/mail.jar:lib/ohj-jewt.jar:lib/oracle_ice.jar:lib/server-bootstrap.jar:lib/servlet-api.jar:lib/wicket-extentions.jar:lib/wicket.jar:lib/wicket-calendar.jar:lib/slf4j-api.jar:lib/slf4j-log4j.jar:lib/joda-time.jar:lib/rmitnl.jar:lib/networktnl.jar com.servoy.j2db.server.ApplicationServer "$@" 1>> server.log 2>> server.log ``` ![Screen Shot 2012-11-13 at 8.32.08 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/5/5c55029e8147a4a3d0b30fbcf81fc98873d45d04.png) ![Screen Shot 2012-11-13 at 8.32.04 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/a/a64d8733c464014dd997fc690887adcd6172427f.png) ![Screen Shot 2012-11-13 at 8.31.57 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/3/3922f524943bb4813141f03502553163fd251d2e.png) ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 12, 2012, 9:40pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/5 "2012-11-12T21:40:03Z")
and htop ![Screen Shot 2012-11-13 at 8.12.32 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/3/31a6611e6e0cc704815b6578158d984981e885d8.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 8:40am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/6 "2012-11-13T08:40:48Z")
The VIRT memory in htop shouldn’t worry you (so maybe I shouldn’t have mentioned it in the first post - thought it was something more measurable); the RES it what is actually used: [more info here](http://serverfault.com/questions/138427/top-what-does-virtual-memory-size-mean-linux-ubuntu). You can use the free command to check the actual used/free memory (second line in the output). [more info here](http://serverfault.com/questions/85470/meaning-of-the-buffers-cache-line-in-the-output-of-free). These used/cache/buffers might actually be the values visible on the memory graph from your first post… At the end of the graph about 7.5 GB were used for 4.5 GB max java application heap size + \> 0.5 GB max PermGen size + thread stack space + internal JVM memory. But then again at the beginning you have 10 GB used… I guess you ran htop before getting the jvisualvm graphs - which would explain the small memory differences (the heap size was decreasing in time in 64 bit Servoy Application Server and used heap was climbing (=\> heap size went up as well probably) in the 32 bit Servoy Application Server). So ```auto |--------------------------------------------------------------------------------------------------------- | (MB) | HTOP USED MEMORY (RES) | JVISUALVM (APROX from Graphs) | | | | USED HEAP | HEAP SIZE | MAX HEAP SIZE | |--------------------------------------------------------------------------------------------------------- | Terracotta Server | 278 | 10-300 | 1024 | 1024 | | Servoy Application Server 32bit | 486 | 150-300 | 512 | 512 | | Servoy Application Server 64bit | 2121 | 300-625 | 1024 | 3072 | ---------------------------------------------------------------------------------------------------------- (HEAP SIZE was ~1750 for 64 bit in the beginning when htop was probably run, so it's ok) ``` I put intervals instead of values for USED HEAP as what you probably see in there is memory going up and down between garbage collection cycles, so most likely the minimum value is the actual used objects space, the rest being yet uncollected garbage. The total OS/RAM memory used by the cluster was \< 3GB and decreasing probably at that time. So the HTOP RES is roughly similar to the HEAP SIZE (above it) for the two Servoy Application Server processes and used Java heap is within the limitations imposed with room to spare (both in increasing heap size and in available free heap size). I suspect that for the Terracotta Server process, the JVM allocated memory differently because of the -server argument and the fixed heap size. In this case RES is close to the actual used heap… So RES in htop and used heap (+ what you see in the PermGen tab) in jvisualvm are the most relevant values. (with the mention that RES might include unused java heap as well and it includes for sure non-heap memory of the application + memory used internally by the JVM) Conclusion: I don’t see problems yet. I would be curious to see all this measured again at the moment when you have 10 GB of used memory in your system as reported by free command. ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 8:45am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/7 "2012-11-13T08:45:49Z")
Total used Java object heap was probably \< 500 MB (not counting garbage). ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 9:03am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/8 "2012-11-13T09:03:15Z")
It’s running at about 10G now. I increased the RAM for TC to 1GB to see if this fixed a data broadcasting issue (see another post [https://www.servoy.com/forum/viewtopic.php?f=5&t=19034](https://www.servoy.com/forum/viewtopic.php?f=5&t=19034) in this forum). ```auto ~$ free total used free shared buffers cached Mem: 12334848 10706828 1628020 0 130568 1197592 -/+ buffers/cache: 9378668 2956180 Swap: 1949688 67136 1882552 ``` My main question is, with x GB of RAM, what are reasonable values for -Xmx so I won’t have the server falling over. I would’ve thought at 12GB of RAM, I should be able to allocate 5GB to Servoy64, but it fell over with those settings so I dropped it to 3GB. ![Screen Shot 2012-11-13 at 7.55.28 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/1X/9aadfff0fd52ad14e07b5711ba14538e4a52aaa8.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 9:12am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/9 "2012-11-13T09:12:16Z")
Can you post what jvisualvm reports as well? ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 9:24am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/10 "2012-11-13T09:24:55Z")
VisualVM screen shots ![Screen Shot 2012-11-13 at 8.20.19 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/5/5f0f25bba0b51cb9f3b555cd7ea080f111a07580.png) ![Screen Shot 2012-11-13 at 8.20.29 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/5/55b15bc7d8c6bcfba61a65dd17cc0c4817178184.png) ![Screen Shot 2012-11-13 at 8.20.40 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/c/c88279a619edc145b45e3ae9bfe9a6cd0a02c122.png) ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 9:26am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/11 "2012-11-13T09:26:16Z")
and free at about the same time ```auto total used free shared buffers cached Mem: 12334848 10424328 1910520 0 133112 1203820 -/+ buffers/cache: 9087396 3247452 Swap: 1949688 67036 1882652 ``` and htop at about the same time ![Screen Shot 2012-11-13 at 8.21.06 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/b/b3a02c7f3e9c58195fae5bc6ffa719982dfe816c.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 10:04am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/12 "2012-11-13T10:04:23Z")
What’s wrong with that last htop? It lists looots of almost identical java processes… ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 10:51am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/13 "2012-11-13T10:51:51Z")
> Andrei Costescu: > What’s wrong with that last htop? It lists looots of almost identical java processes… Ah, forgot to hide userland processes ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 12:30pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/14 "2012-11-13T12:30:16Z")
Also it doesn’t seem to be the same server. TC Server and one of the app. servers are running for 12 + hours already. What you have shown earlier is from another server, right? I see the overall free memory increased by 300 MB in the 20 or so min between the last 2 free commands (so the htop shows slightly higher values at that time). Here is the new situation based on the htop before the jvisualvm screenshots: ```auto ---------------------------------------------------------------------------------------------------------- | (MB) | HTOP USED MEMORY (RES) | JVISUALVM (APROX from Graphs) | | | | USED HEAP | HEAP SIZE | MAX HEAP SIZE | |--------------------------------------------------------------------------------------------------------- | Terracotta Server | 1269 | 500-700 | 1024 | 1024 | | Servoy Application Server 32bit | 2053 | 250-350 | 512 | 512 | | Servoy Application Server 64bit | 5477 | 850-900 | 2160 | 3072 | ---------------------------------------------------------------------------------------------------------- ``` So used Java heap is 1600 - 1950 MB. Java heap sizes sum up to ~3700 MB. Yet the used RAM reported by htop is \> 8.7GB… The remaining off-heap 5 GB seems too much to me (for thread/permgen/internal memory). I wonder what the JVM stores in there… is it extreme optimisations or is it a bug… Did you try newer JVM versions (e.g. latest 1.6)? I’ll also post a question on the Terracotta forums to see if Terracotta might have something to do with it (maybe something to do with DGC). What are the values of permgen reported in jvisualvm (just values I don’t think screenshots are needed for this)? I guess they are under the max 256 MB / process. Do you have a crash log? Which of the 3 processes crashes eventually? ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 2:48pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/15 "2012-11-13T14:48:29Z")
What is the Terracotta version? ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 8:27pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/16 "2012-11-13T20:27:22Z")
Here’s a fresh lot of data, all taken at ~7:23 definitely all from the same server (I only have 1 linux server running at the moment) ```auto total used free shared buffers cached Mem: 12334848 12198620 136228 0 295340 2308332 -/+ buffers/cache: 9594948 2739900 Swap: 1949688 58576 1891112 ``` htop [attachment=0]Screen Shot 2012-11-14 at 7.22.56 AM.png[/attachment] ![Screen Shot 2012-11-14 at 7.22.56 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/d/d9bacfa021f1d7a124c982b82f5f32a0bfb883b2.png) ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 13, 2012, 8:34pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/17 "2012-11-13T20:34:21Z")
VisualVM graphs at the same time, low load on the server, low memory use reported within Servoy, but almost no free RAM reported with free or htop. Servoy32 PermGen Memory Size: 111,017,984 B Used: 90,002,912 B Max: 268,435,456 B Servoy64 PermGen Memory Size: 108,199,936 B Used: 108,195,728 B Max: 268,435,456 B TC PermGen Memory Size: 38,928,384 B Used: 37,193,592 B Max: 85,983,232 B and JVM Information (Servoy64) java.vm.name=Java HotSpot™ 64-Bit Server VM java.version=1.6.0\_26 java.vm.info=mixed mode java.vm.vendor=Sun Microsystems Inc. JVM Information (Servoy32) java.vm.name=Java HotSpot™ Server VM java.version=1.6.0\_26 java.vm.info=mixed mode java.vm.vendor=Sun Microsystems Inc. ![Screen Shot 2012-11-14 at 7.24.33 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/1X/5d1e124e2043eb98806dd4c7f4798670b9a7869c.png) ![Screen Shot 2012-11-14 at 7.24.15 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/9/9fabb8902382c769f1c6e6f69642ba369e8d4418.png) ![Screen Shot 2012-11-14 at 7.23.39 AM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/1/17c93b6a69f7d8df0a21369446d9f82a6b8d0d12.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 13, 2012, 9:11pm UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/18 "2012-11-13T21:11:56Z")
So it’s basically the same. Used Java heap low, used OS memory very high. I’ll need to run some stuff locally and see if I get the same but it really seems to be JVM (or Terracotta) related. It’s like the JVM forgets to return memory back to the OS. I’m not sure that this causes the crashes though - if the Java heap can use this strange already allocated space when it needs to. What version of Terracotta do you use? Any crash logs so that we can see which one crashed exactly and why? It can be seen in the Terracotta server heap (that seems to be slowly but constantly increasing towards the max) that it didn’t yet run the distributed garbage collector. I think by default, without any tuning it will run once a day. I mentioned in the other thread how this can be improved with the 2 settings. ---
**Author:** ![antonio](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@antonio](https://forum.servoy.com/u/antonio)\ **Post date:** [November 14, 2012, 1:22am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/19 "2012-11-14T01:22:25Z")
Hello again Andrei, From the log, its Terracotta 3.7.0 We haven’t had any servoy application crashes since increasing the RAM to 12GB, only at 8GB a few weeks ago. You’d think I should be able to allocate more than 3G out of the 12G to Servoy64. I’ll increase the Xmx setting for Servoy64 tonight and see what that does. Looking at TC RAM usage in Visual VM, it appear to increase until it hits 90% eg around 11:27 then does a cleanup, which seems to take about 10 minutes… ```auto 2012-11-14 11:21:28,374 [Statistics Logger] INFO com.terracottatech.dso - memory free : 177.960243 MB 2012-11-14 11:21:28,380 [Statistics Logger] INFO com.terracottatech.dso - memory used : 833.039757 MB 2012-11-14 11:21:28,381 [Statistics Logger] INFO com.terracottatech.dso - memory max : 1011.000000 MB 2012-11-14 11:27:42,026 [TC Memory Monitor] WARN tc.operator.event - NODE : localhost:9510 Subsystem: MEMORY_MANAGER Message: Current Memory usage(94%) crossed critical threshold(90%). 2012-11-14 11:36:28,374 [Statistics Logger] INFO com.terracottatech.dso - memory free : 653.333107 MB 2012-11-14 11:36:28,374 [Statistics Logger] INFO com.terracottatech.dso - memory used : 332.104393 MB 2012-11-14 11:36:28,374 [Statistics Logger] INFO com.terracottatech.dso - memory max : 985.437500 MB 2012-11-14 11:36:36,582 [Server Map Periodic Evictor] INFO tc.operator.event - NODE : localhost:9510 Subsystem: DCV2 Message: DCV2 Eviction - Time taken (msecs)=0, Number of entries evicted=0, Number of segments over threshold=0, Total Overshoot=0 2012-11-14 11:36:36,582 [Server Map Periodic Evictor] INFO com.tc.objectserver.impl.ServerMapEvictionStatsManager - Server Map Periodic eviction - Time taken (msecs): 0, Number of segments under threshold: 0, Number of segments over threshold: 0, Total overshoot: 0, Total number of samples requested: 0, Number of segments where eviction happened: 0, Total number of evicted entries: 0 ``` I can try forcing the GC more often with your tips, but if it _is_ happening anyway will it help? [attachment=0]Screen Shot 2012-11-14 at 12.16.58 PM.png[/attachment] ![Screen Shot 2012-11-14 at 12.16.58 PM.png](https://canada1.discourse-cdn.com/flex010/uploads/servoy/original/2X/1/1ebf5d4da323c1b56b317ca829d466788c555480.png) ---
**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\ **Post date:** [November 14, 2012, 8:04am UTC](https://forum.servoy.com/t/servoy-memory-usage-question/16728/20 "2012-11-14T08:04:04Z")
The DGC tuning could help avoid TC server disk caching - which might slow down the TC server a bit (if it tends to go over Xmx). I don’t think that it takes 10 min for that DGC to run, it’s just around 10 min between the memory logger triggers. You can enable DGC logging as well - see the link for modifying the DGC interval on [the other thread](https://www.servoy.com/forum/viewtopic.php?f=5&t=19034). Btw. the DGC only collects shared objects that have already been collected by GCs in the JVMs that used them, so DGC and JVM GCs should be tuned together. No use to have DGC clean every 10 min but JVM GCs clean much less often. I thought you got crashes with 12 GB or RAM as well. If I remember correctly from the other discussion the 8 GB RAM crash was when you had configured Xmx (5G + 512M + 512M) + max permGen (~400M), so around 6 GB for the whole cluster and you already had up to 2 GB used. So then you were really at the limit with Java heap and permGen only, without taking into account other memory needs of the JVMs. Yes, you should be able to increase the Xmx setting for Servoy 64. Let us know how it goes. [Next page](https://forum.servoy.com/t/servoy-memory-usage-question/16728.md?page=2)