I'm a developer in a large company that has some legacy code that requires a very large ammount of memory on export functions. To address this, ini_set('memory_limit', '4G'); is used.
The problem is that the script crashes with memory exaustion. If I set the limit to 2G, the script runs to the end. It doesn't even reaches 1GB peak memory usage.
Since the code is versioned and shared with the rest of the company I can't change the limit and changing it on my local install is cumbersome.
My question is: what can make a script crashes with 4GB limit but not 2GB?
PS: my setup is a virtualbox machine running Debian with nginx and php-fpm. The vm has 4GB RAM (although changing this doesn't seem to do any difference).
[update]
Created a new virtual machine with an 64 bits operation system and if I set the vm memory to 2GB it works. (If i use 4GB it doesn't).
Since i'm ok with 2GB, i'll close this issue.
It is a natural limitation: 2 or even 4 Gbs of address space are used for file mapping also which takes some memory pages.
The ultimate solution would be to use the 64-bit PHP interpreter (i.e., switch to 64-bit system, if possible).
Maybe you are on a 32bit system?
Well if your VM only has 4GB, then you probably should give it more memory.
On the 32 bit system 4GB is the limit of memory space. I guess that there can be some memory violations when PHP tries to get 4GB memory.
Related
I'm checking a server that has 32gb of ram and I see 99% memory usage.
The machine is used with IIS, MongoDB and ElasticSearch.
None of the processes seemed to be that big. The largest was MongoDB at about 1gb.
So, I shut down everything.. and now that memory usage is 88%
After a reboot, with all services running, the memory usage is 23%
Those are the largest processes on the system, with everything being shutdown. As you can see, everything is very small, but most of the ram remains gone.
How can I track what is eating up all the ram? I tried process explorer, but it doesn't give me any more useful info.
Try to use RAMMAP from sysinternals it will give you more details about memory usage. Like metaFile for example.
Elasticsearch generally a lot of the available RAM to cache search results aggregation. This is to avoid memory swapping. It's very evident and observable in LINUX servers. Thus it's recommended using ES in separate server in production with heavy usage.
So please try and check cache memory once.
Have a look at the Heap size allotted to Elasticsearch. You could check the values of -Xms and -Xmx in jvm.options file. Usually, 50% of physical RAM is allotted to ES and with bootstrap.memory_lock set to true, it locks the RAM. Ideally, as another answer mentions, Elasticsearch should be run in its own machine.
I am not able to find maria DB recommended RAM,disk,number of Core capacity. We are setting up initial level and very minimum data volume. So just i need maria DB recommended capacity.
Appreciate your help!!!
Seeing that over the last few years Micro-Service architecture is rapidly increasing, and each Micro-Service usually needs its own database, I think this type of question is actually becoming more appropriate.
I was looking for this answer seeing that we were exploring the possibility to create small databases on many servers, and was wondering for interest sake what the minimum requirements for a Maria/MySQL DB would be...
Anyway I got this helpful answer from here that I thought I could also share here if someone else was looking into it...
When starting up, it (the database) allocates all the RAM it needs. By default, it
will use around 400MB of RAM, which isn’t noticible with a database
server with 64GB of RAM, but it is quite significant for a small
virtual machine. If you add in the default InnoDB buffer pool setting
of 128MB, you’re well over your 512MB RAM allotment and that doesn’t
include anything from the operating system.
1 CPU core is more than enough for most MySQL/MariaDB installations.
512MB of RAM is tight, but probably adequate if only MariaDB is running. But you would need to aggressively shrink various settings in my.cnf. Even 1GB is tiny.
1GB of disk is more than enough for the code and minimal data (I think).
Please experiment and report back.
There are minor differences in requirements between Operating system, and between versions of MariaDB.
Turn off most of the Performance_schema. If all the flags are turned on, lots of RAM is consumed.
20 years ago I had MySQL running on my personal 256MB (RAM) Windows box. I suspect today's MariaDB might be too big to work on such tiny machine. Today, the OS is the biggest occupant of any basic machine's disk. If you have only a few MB of data, then disk is not an issue.
Look at it this way -- What is the smallest smartphone you can get? A few GB of RAM and a few GB of "storage". If you cut either of those numbers in half, the phone probably cannot work, even before you add apps.
MariaDB or MySQL both actually use very less memory. About 50 MB to 150 MB is the range I found in some of my servers. These servers are running a few databases, having a handful of tables each and limited user load. MySQL documentation claims in needs 2 GB. That is very confusing to me. I understand why MariaDB does not specify any minimum requirements. If they say 50 MB there are going to be a lot of folks who will want to disagree. If they say 1 GB then they are unnecessarily inflating the minimum requirements. Come to think of it, more memory means better cache and performance. However, a well designed database can do disk reads every time without any performance issues. My apache installs (on the same server) consistently use up more memory (about double) than the database.
I have one of those first alu iMacs with 2+2 GB ram. I use Vagrant to emulate advanced development environments, separated for different jobs.
When I have just one vagrant process running in the background, the computer gets to be slow as hell, because it is always out of memory.
The question is: can I use vagrant (or any app) to run only on swap memory, so it leaves all the memory for the os and other apps?
If there is any solution, how can I do that?
The short answer is: No, a process can not run in swap completely.
Processes must have their data in RAM for the CPU to be able to operate on it, infrequently used data is moved out to swap space when there's no longer space available in memory for everything that's loaded.
You could create a larger swap space and use ulimit to limit the amount of memory used by processes (i.e. force them into swap earlier), but this doesn't really address the root of your problem - that you're pretty much at the limit of your 4GB of memory.
Keep in mind that using swap space will always produce performance problems as (even with SSDs) reading from disk is far slower than reading from memory.
Short of upgrading to more memory, you could:
Reduce the amount of memory allocated by your vagrant box;
Use OS X's Activity Monitor to identify and close any programs/processes that are not in use but are still using memory.
but, again, these are just stop-gap solutions.
Simple answer is no.
Control swappiness has to be done within the VM, for example Linux, echo 100 > /proc/sys/vm/swappiness to set swap strategy to most aggressive mode. Remember, you have no control over where processes are running (physical memory VS swap)
However, by doing this, your host/guest will still be slow as hell as simply you don't have enough physical memory.
The ultimate solution is to add more RAM to your iMAC ;-D
We're running into a strange problem. Our ASP.NET application is running on 64-bit Windows 2008/IIS7 machine with 16Gb of RAM. When w3wp.exe process reaches 4Gb (we track it simple via Task Manager on the server) - Out of Memory exeption is thrown even though there's a plenty of memory still available.
Is there a known issue were ASP.NET process is limited to 4Gb of memory on 64bit system (and using 64bit app pool)?
Is there any way to lift that limit?
It kind of sounds like you have an undisposed resource somewhere that ends up getting garbage collected eventually, but not quickly enough for your needs. Do you reuse any SQLConnection objects? Or MailClient objects? Or unmanaged Image objects?
As for the lower-than-expected memory limit, there are two types of memory use by a ASP.NET app. One is reserved memory and the other is actually used memory. I believe the task manager tracks actual memory use, but reserved memory probably also has a limit. To find out how much reserved memory your process is taking up, go to IIS7, click on the server (the top level, above app pools and sites folder), then click the Processes option and then click your app's process. It should show you CPU use, number of requests and memory usage (both reserved and actual).
I'm running a Windows 2008 server (a VPS with 1GB of RAM), with SQL Server Express and IIS 7 installed. On it I'm hosting a NopCommerce 1.7 website, with a database of around 26 000 products.
Right now I'm the only user of the website (it's in development) and I'm getting rather bad performance from it. To be more specific every time I make a request, the worker process goes to 90-100% CPU usage for a few seconds. Is it me or this is a lot for a 1 user NopCommerce website? Any ideas why this happens and what I can do to rectify it or further investigate?
PS: the worker process uses between 100MB-400MB of memory (private working set), and SQL Server with this database, around 160MB. Do you have any suggestions other then the obvious one to get more RAM? I intend to get one more GB but I fear this will not solve the cpu usage problem.
You've already stated you're going to get more RAM, but don't be surprised how much a lack of RAM can impact the CPU. If your RAM is not able to hold large objects efficiently because of lack of space (and I'd say using 40% of available RAM qualifies), then the CPU has to work harder to page things in and out of virtual memory. 90% is a little overkill for this, but with the server specs you give it's not impossible.
The most likely problem is that there is a hole in your code somewhere. My guess is that you have either an infinite loop or a direct memory leak (resources open during requests that aren't closed perhaps?). Your best bet would be to get the IIS Debug Diagnostics tool, install it and set up reports to find out what is going on directly on the server.