As i am new for neo4j i have been facing the follwing errors.
1.when i start neo4j it gives the follwoing message.
WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.
Using additional JVM arguments: -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dlog4j.configuration=file:conf/log4j.properties -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled
note :i tried to edit the file ,/etc/security/limits.conf and added
root soft nofile 40000
root hard nofile 40000
but not solved
2.in the messages.log file has multiple records like below.
2014-07-16 07:07:49.688+0000 WARN [o.n.k.EmbeddedGraphDatabase]: GC Monitor: Application threads blocked for an additional 111ms [total block time: 56.805s]
2014-07-16 07:09:02.778+0000 WARN [o.n.k.EmbeddedGraphDatabase]: GC Monitor: Application threads blocked for an additional 103ms [total block time: 56.908s]
The problem is some time suddently the server CPU goes high and taking few hours to get down.Please give me a proper idea.
Thanks
Az
1) Best practice on Ubuntu is not setting this in ยด/etc/security/limits.confdirectly, instead create a file/etc/security/limits.d/neo4j.conf` containing:
* soft nofile 40000
* hard nofile 40000
2) This is more information for you how much time is spent in GC. If a single pause gets too long it's an indication to tweak JVM settings. Stop times of 100ms is not really concerning in most cases. However the "total block time" of almost one minute might require further investigation.
Related
I have a ktor app. I works fine when I run it in development mode. I package it in a docker image by copying over what the gradle application plugin provided. That also works fine on my local machine 8 cores. But now the strange part. When I do exactly the same thing on a rented V-Server also running Ubuntu-20.04 like my local system, ktor is incredible slow.
docker-compose logs server:
server | 2021-08-24 08:00:23.337 [main] INFO ktor.application - Autoreload is disabled because the development mode is off.
server | 2021-08-24 08:25:35.048 [main] INFO ktor.application - Autoreload is disabled because the development mode is off.
server | 2021-08-24 09:18:48.246 [main] INFO c.e.e.s.TemplateStore - Starting to parse Sentences
server | 2021-08-24 09:18:48.345 [main] INFO c.e.e.s.TemplateStore - Finished parsing sentences
server | 2021-08-24 09:18:48.346 [main] INFO ktor.application - Responding at http://0.0.0.0:8080
server | 2021-08-24 09:18:48.347 [main] INFO ktor.application - Application started in 3193.32 seconds.
Application started in 3193.32 seconds
The source code can be found here https://github.com/1-alex98/whatisthat . It has a docker-compose.yml defining the whole docker container being started.
Local system 32 gb ram + 8 cores . V-Server 4 gb Ram + 2 cores (htop shows pleinty of resources are free).
I am looking for ideas on what in the world could cause this behavior. Or ways to debug it.
Update:
Seems to read a file forever:
"main" #1 prio=5 os_prio=0 cpu=652.14ms elapsed=173.92s tid=0x00007f01d4016000 nid=0xe runnable [0x00007f01dace6000]
java.lang.Thread.State: RUNNABLE
at java.io.FileInputStream.readBytes(java.base#11.0.12/Native Method)
at java.io.FileInputStream.read(java.base#11.0.12/FileInputStream.java:279)
at java.io.FilterInputStream.read(java.base#11.0.12/FilterInputStream.java:133)
at sun.security.provider.NativePRNG$RandomIO.readFully(java.base#11.0.12/NativePRNG.java:424)
at sun.security.provider.NativePRNG$RandomIO.ensureBufferValid(java.base#11.0.12/NativePRNG.java:526)
at sun.security.provider.NativePRNG$RandomIO.implNextBytes(java.base#11.0.12/NativePRNG.java:545)
- locked <0x00000000c7571158> (a java.lang.Object)
at sun.security.provider.NativePRNG$Blocking.engineNextBytes(java.base#11.0.12/NativePRNG.java:268)
at java.security.SecureRandom.nextBytes(java.base#11.0.12/SecureRandom.java:751)
at kotlin.random.AbstractPlatformRandom.nextBytes(PlatformRandom.kt:47)
at kotlin.random.Random.nextBytes(Random.kt:260)
at com.example.routes.websocket.WebsocketRoutingKt.<clinit>(WebsocketRouting.kt:40)
at com.example.plugins.RoutingKt$routing$1.invoke(Routing.kt:13)
at com.example.plugins.RoutingKt$routing$1.invoke(Routing.kt:11)
at io.ktor.routing.Routing$Feature.install(Routing.kt:106)
at io.ktor.routing.Routing$Feature.install(Routing.kt:88)
at io.ktor.application.ApplicationFeatureKt.install(ApplicationFeature.kt:68)
at io.ktor.routing.RoutingKt.routing(Routing.kt:129)
at com.example.plugins.RoutingKt.routing(Routing.kt:11)
at com.example.ApplicationKt$main$1.invoke(Application.kt:18)
at com.example.ApplicationKt$main$1.invoke(Application.kt:14)
at io.ktor.server.engine.internal.CallableUtilsKt.executeModuleFunction(CallableUtils.kt:50)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$launchModuleByName$1.invoke(ApplicationEngineEnvironmentReloading.kt:317)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$launchModuleByName$1.invoke(ApplicationEngineEnvironmentReloading.kt:316)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.avoidingDoubleStartupFor(ApplicationEngineEnvironmentReloading.kt:341)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.launchModuleByName(ApplicationEngineEnvironmentReloading.kt:316)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.access$launchModuleByName(ApplicationEngineEnvironmentReloading.kt:30)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$instantiateAndConfigureApplication$1.invoke(ApplicationEngineEnvironmentReloading.kt:304)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading$instantiateAndConfigureApplication$1.invoke(ApplicationEngineEnvironmentReloading.kt:295)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.avoidingDoubleStartup(ApplicationEngineEnvironmentReloading.kt:323)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.instantiateAndConfigureApplication(ApplicationEngineEnvironmentReloading.kt:295)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.createApplication(ApplicationEngineEnvironmentReloading.kt:136)
at io.ktor.server.engine.ApplicationEngineEnvironmentReloading.start(ApplicationEngineEnvironmentReloading.kt:268)
at io.ktor.server.netty.NettyApplicationEngine.start(NettyApplicationEngine.kt:174)
at com.example.ApplicationKt.main(Application.kt:21)
at com.example.ApplicationKt.main(Application.kt)
It is a fresh rented server but I guess something is wrong with it
docker-compose being slow and my program not starting seemed to be due to insufficient(not good enough) input to /dev/urandom. Installing https://github.com/smuellerDD/jitterentropy-rngd resolved the problem.
I have CentOS 6.8, Cassandra 3.9, 32 GB RAM. When I start Cassandra and once it is started, it starts consuming the memory and start adding up 'Cached' memory value when I start querying from CQLSH or Apache Spark and in this process, very less memory remain for other processing like cron execution.
Here are some details from my system
free -m
total used free shared buffers cached
Mem: 32240 32003 237 0 41 24010
-/+ buffers/cache: 7950 24290
Swap: 2047 25 2022
And here is the output of top -M command
top - 08:54:39 up 5 days, 16:24, 4 users, load average: 1.22, 1.20, 1.29
Tasks: 205 total, 2 running, 203 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.5%us, 1.2%sy, 19.8%ni, 75.3%id, 0.1%wa, 0.1%hi, 0.0%si, 0.0%st
Mem: 31.485G total, 31.271G used, 219.410M free, 42.289M buffers
Swap: 2047.996M total, 25.867M used, 2022.129M free, 23.461G cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
14313 cassandr 20 0 595g 28g 22g S 144.5 91.3 300:56.34 java
You can see only 220 MB is left and 23.46 is cached.
My question is how to configure Cassandra so that it can use 'cached' memory to certain value and leave more RAM available for other processes.
Thanks in advance.
In linux in general cached memory as your 23g is just really fine. This memory is used as filesystem cache and so on - not by cassandra itself. Linux systems tend to use all available memory.
This helps to speed up your system in many ways to prevent disk reads.
You can still use the cached memory - just start processes and use your ram, the kernel will free it immediatly.
You can set the sizes in cassandra-env.sh under conf folder. This article should help. http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsTuneJVM.html
The logs for my Cloud Dataflow job contain multiple messages of the form:
[GC (Allocation Failure) [PSYoungGen: 72352K->160K(71168K)]
120584K->48392K(158720K), 0.0022739 secs] [Times: user=0.00 sys=0.00,
real=0.00 secs]
What does this mean? What should I do about it?
The "Allocation Failure" message is a completely normal part of Java memory management; it just means the JVM has run out of memory and needs to trigger a GC. Unless there is already a reason to suspect memory problems, the "Java GC" log is generally not worth looking at for Dataflow pipelines.
Please see Java GC (Allocation Failure) for additional information.
I currently have a rails app set up on a Digital Ocean VPS (1GB RAM) trough Cloud 66. The problem being that the VPS' memory runs full with Passenger processes.
The output of passenger-status:
# passenger-status
Version : 4.0.45
Date : 2014-09-23 09:04:37 +0000
Instance: 1762
----------- General information -----------
Max pool size : 2
Processes : 2
Requests in top-level queue : 0
----------- Application groups -----------
/var/deploy/cityspotters/web_head/current#default:
App root: /var/deploy/cityspotters/web_head/current
Requests in queue: 0
* PID: 7675 Sessions: 0 Processed: 599 Uptime: 39m 35s
CPU: 1% Memory : 151M Last used: 1m 10s ago
* PID: 7686 Sessions: 0 Processed: 477 Uptime: 39m 34s
CPU: 1% Memory : 115M Last used: 10s ago
The max_pool_size seems to be configured correctly.
The output of passenger-memory-stats:
# passenger-memory-stats
Version: 4.0.45
Date : 2014-09-23 09:10:41 +0000
------------- Apache processes -------------
*** WARNING: The Apache executable cannot be found.
Please set the APXS2 environment variable to your 'apxs2' executable's filename, or set the HTTPD environment variable to your 'httpd' or 'apache2' executable's filename.
--------- Nginx processes ---------
PID PPID VMSize Private Name
-----------------------------------
1762 1 51.8 MB 0.4 MB nginx: master process /opt/nginx/sbin/nginx
7616 1762 53.0 MB 1.8 MB nginx: worker process
### Processes: 2
### Total private dirty RSS: 2.22 MB
----- Passenger processes -----
PID VMSize Private Name
-------------------------------
7597 218.3 MB 0.3 MB PassengerWatchdog
7600 565.7 MB 1.1 MB PassengerHelperAgent
7606 230.8 MB 1.0 MB PassengerLoggingAgent
7675 652.0 MB 151.7 MB Passenger RackApp: /var/deploy/cityspotters/web_head/current
7686 652.1 MB 116.7 MB Passenger RackApp: /var/deploy/cityspotters/web_head/current
### Processes: 5
### Total private dirty RSS: 270.82 MB
.. 2 Passenger RackApp processes, OK.
But when I use the htop command, the output is as follows:
There seem to be a lot of Passenger Rackup processes. We're also running Sidekiq with the default configuration.
New Relic Server reports the following memory usage:
I tried tuning Passenger settings, adding a load balancer and another server but honestly don't know what to do from here. How can I find out what's causing so much memory usage?
Update: I had to restart ngnix because of some changes and it seemed to free quite a lot of memory.
Press Shift-H to hide threads in htop. Those aren't processes but threads within a process. The key column is RSS: you have two passenger processes at 209MB and 215MB and one Sidekiq process at 154MB.
Short answer: this is completely normal memory usage for a Rails app. 1GB is simply a little small if you want multiple processes for each. I'd cut down passenger to one process.
Does your application create child processes? If so, then it's likely that those extra "Passenger RackApp" processes are not actually processes created by Phusion Passenger, but are in fact processes created by your own app. You should double check whether your app spawns child processes and whether you clean up those child processes correctly. Also double check whether any libraries you use, also properly clean up their child processes.
I see that you're using Sidekiq and you've configured 25 Sidekiq processes. Those are also eating a lot of memory. A Sidekiq process eats just as much memory as a Passenger RackApp process, because both of them load your entire application (including Rails) in memory. Try reducing the number of Sidekiq processes.
I am trying to figure out what is wrong with my Debian server - I am getting warnings of having not enough free memory - top (as you can see below) is saying that 1.8G is consumed, but I am unable to find which application is responsible for it. There is only Tomcat running, which consumes, according to top, ~25 % and so 530m. But There is more than 1 GB left, which I am unable to find!
Tasks: 54 total, 1 running, 53 sleeping, 0 stopped, 0 zombie
Cpu(s):100.0%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2150400k total, 1877728k used, 272672k free, 0k buffers
Swap: 0k total, 0k used, 0k free, 0k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3271 root 18 0 1559m 530m 12m S 0 25.2 1:44.31 java
1568 mysql 15 0 270m 71m 7332 S 0 3.4 0:50.79 mysqld
(Full top output here)
Linux systems always try to use as much ram as available for various functions like caching of executables our even just page reads from disk. That's what you bought your fast RAM for after all.
You can find out more about your system by doing a
cat /proc/meminfo
More info in this helpful blog post
If you find out a lot is used in cache then you don't have to worry about the system.if individual processes warn you about memory issues then you'll have to check their settings for any memory limiting settings. Many server processes have those, like php or java based processes.
Questions of this nature are also probably more at home at https://serverfault.com/
As i see, your 'Free' command returned NO swap space
Swap: 0k total, 0k used, 0k free, 0k cached
either there is no swap partition available
this swap space is not mounted
one can manual make a swapfile
and mount this file as becoming the active swap
howto make swap
To test your real usage
reboot the machine and
test the used amount
retest after 1 hour
some processes are memory hoggs
like apache or ntop
refer:
check memory
display sorted
memory usage