I got mongodb version 3.0 on linux redhat 6. The storage engine is MMAPv1.
I checked mongo memory usage on the server. I notice that virtual memory is 10 Gb which is far from mapped memory that is 4 Gb.
Is this situation correct or mongo server is running suboptimal?
It should be related to the glibc new virtual memory management since glibc2.10.
see here .
https://www.ibm.com/developerworks/community/blogs/kevgrig/entry/linux_glibc_2_10_rhel_6_malloc_may_show_excessive_virtual_memory_usage?lang=en
In a nutshell, the new malloc will allocate by default 8*cores*64MB on 64bit system for thread memory pool.
Related
I'm currently using a combination of qemu-kvm, libvirtd, and virt-manager to host some virtual RHEL 6 machines. When I go ahead and attempt to bump the ram usage up above 4gb, the machines fail to start. What would even be the cause of this? Any information is helpful.
I'm running a 10 core, 3GHz Xeon processor, with 64 GB of ram.
Hi I am trying to find the limit for xms and xmx on a 64 bit 2008R2 platform.
I have limited knowledge of this area.
Can anyone tell me if there are any issues with setting xmx and xms to 18gig. I have read about issues with garbage collection. The server has 24gig.
Thanks
Sid
I am running 65536M on 2008 R2 64-bit with no issues. Machine has 32GB physical (well, it's actually a VM, so it's virtual, but what isn't?). I actually came to your question to see if going to 96GB on a 32GB VM would be an issue, other than more disk thrashing.
as here mention, mongodb has limitation of datasize to 2GB in 32-bit machine with one single mongod instance. But I wonder 32-bit machine has 4GB addressable space in theory, and mongod can use this 4GB instead of 2GB for virtual memory usage. So why the answer is 2GB, not 4GB?
4Gb of addressable space is not the same as the memory space available for memory-mapped files opened by user applications. Some of the addressable space is reserved for the O/S kernel and memory-mapped devices such as video cards.
For example, 32-bit Windows limits user mode (and thus memory-mapped files) to ~2Gb RAM and total system RAM to ~3.5Gb.
For more reading, see:
Coding Horror: Dude, Where's My 4 Gigabytes of RAM?
MSDN: Managing Memory-Mapped Files
MSDN: Memory-Mapped Files
The majority of modern desktop and server environments starting moving to 64-bit almost a decade ago (see 64-bit operating system timeline on Wikipedia) so this isn't a limit that practically affects deployment.
You would only want to use 32-bit MongoDB in a development environment with limited data.
32-bit MongoDB processes are limited to about 2 gb of data. This has come as a surprise to a lot of people who are used to not having to worry about that. The reason for this is that the MongoDB storage engine uses memory-mapped files for performance.
By not supporting more than 2gb on 32-bit, we’ve been able to keep our code much simpler and cleaner. This greatly reduces the number of bugs, and reduces the time that we need to release a 1.0 product.
http://blog.mongodb.org/post/137788967/32-bit-limitations
Im still fighting with mongoDB and I think this war will end is not soon.
My database has a size of 15.95 Gb;
Objects - 9963099;
Data Size - 4.65g;
Storage Size - 7.21g;
Extents - 269;
Indexes - 19;
Index Size - 1.68g;
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Quad Xeon E3-1220 4 × 3.10 GHz / 8Gb
For me to pay dearly for a dedicated server.
On VPS 6GB memory, database is not imported.
Migrate to the cloud service?
https://www.dotcloud.com/pricing.html
I try to pick up the rate but there max 4Gb memory mongoDB (USD 552.96/month o_0), I even import your base can not, not enough memory.
Or something I do not know about cloud services (no experience with)?
Cloud services are not available to a large database mongoDB?
2 x Xeon 3.60 GHz, 2M Cache, 800 MHz FSB / 12Gb
http://support.dell.com/support/edocs/systems/pe1850/en/UG/p1295aa.htm
Will work my database on that server?
This is of course all the fun and get the experience in the development, but already beginning to pall ... =]
You shouldn't have an issue with a db of this size. We were running a mongodb instance on Dotcloud with 100's of GB of data. It may just be because Dotcloud only allow 10GB of HDD space by default per service.
We were able to backup and restore that instance on 4GB of RAM - albeit that it took several hours
I would suggest you email them directly support#dotcloud.com to get help increasing the HDD allocation of your instance.
You can also consider using ObjectRocket which is a MOngoDB as a service. For a 20Gb database the price is $149 per month - http://www.objectrocket.com/pricing
some friends are telling me that Workstation does allocate memory(RAM) from Windows startup even without starting VMWare Workstation is that true?
I have searched the net and I still have no answer.
It allocates virtual memory. Whether or not that memory is backed by physical RAM is up to the operating system.