Mongo in container: how to manage memory
We have an apache/mongo architecture, organized around Docker. So far everything was fine, but with the bases growing, we now face new challenges.
Right now, we have 3 projects in production, with a total of 6 containers (1 apache container and 1 mongo container per project).
The problem we face is that each mongo container think they have 21GB of memory, so they try to use 80% of it
So the solution for me was to restart one of the container with a memory limit given to the mongo process :
--wiredTigerCacheSizeGB 7
The problem with that solution is that the limit is fixed for each mongo container. If one base needs more memory, I would have to restart the container with another value.
So please I have some questions. I think these questions might interest others in general, since I didn't find anything about that precisely on the Internet :
1) Is there a global solution to balance memory between mongo container?
That is, automatically? (without manual supervision, where I've got to check the I/O on disks)
And also, without restarting the container?
2) Are Cache limitations really useful?
Since the OS limits the container anyway, should I remove the limit and disable the alarms I get? (Not doing that anyway)
3) Is it really useful to have one container per base?
Would it be more practical, under the aspect of memory, to have one big mongo container for all three bases?
What would be the pros and cons for both solutions?
One mongo container for all projects bases
Pros:
Easier to manage
Easier to balance memory
Cons:
Less secure
One mongo container per base:
Pros:
More secure
Easier to backup? (not really)
Cons:
Difficult to handle memory
4) We are having a more general debate about how memory should relate to disk with mongo.
Personally, I don't think it's a problem if the base on disk is bigger than its footprint in memory, ie it's OK to have parts of database on disk that are rarely touched and thus won't find themselves in memory.
My devs think that size on disk should be the size in memory. That is, if I have a 40GB databases, I should have 40GB of memory, which appear unrealistic to me.
What is your opinion on that?
Thank you everyone for their answers!
mongodb docker memory-management
asked Nov 12 '18 at 14:53
BibeloBibelo
113
add a comment |
We have an apache/mongo architecture, organized around Docker. So far everything was fine, but with the bases growing, we now face new challenges.
Right now, we have 3 projects in production, with a total of 6 containers (1 apache container and 1 mongo container per project).
The problem we face is that each mongo container think they have 21GB of memory, so they try to use 80% of it
So the solution for me was to restart one of the container with a memory limit given to the mongo process :
--wiredTigerCacheSizeGB 7
The problem with that solution is that the limit is fixed for each mongo container. If one base needs more memory, I would have to restart the container with another value.
So please I have some questions. I think these questions might interest others in general, since I didn't find anything about that precisely on the Internet :
1) Is there a global solution to balance memory between mongo container?
That is, automatically? (without manual supervision, where I've got to check the I/O on disks)
And also, without restarting the container?
2) Are Cache limitations really useful?
Since the OS limits the container anyway, should I remove the limit and disable the alarms I get? (Not doing that anyway)
3) Is it really useful to have one container per base?
Would it be more practical, under the aspect of memory, to have one big mongo container for all three bases?
What would be the pros and cons for both solutions?
One mongo container for all projects bases
Pros:
Easier to manage
Easier to balance memory
Cons:
Less secure
One mongo container per base:
Pros:
More secure
Easier to backup? (not really)
Cons:
Difficult to handle memory
4) We are having a more general debate about how memory should relate to disk with mongo.
Personally, I don't think it's a problem if the base on disk is bigger than its footprint in memory, ie it's OK to have parts of database on disk that are rarely touched and thus won't find themselves in memory.
My devs think that size on disk should be the size in memory. That is, if I have a 40GB databases, I should have 40GB of memory, which appear unrealistic to me.
What is your opinion on that?
Thank you everyone for their answers!
mongodb docker memory-management
asked Nov 12 '18 at 14:53
BibeloBibelo
113
add a comment |
We have an apache/mongo architecture, organized around Docker. So far everything was fine, but with the bases growing, we now face new challenges.
Right now, we have 3 projects in production, with a total of 6 containers (1 apache container and 1 mongo container per project).
The problem we face is that each mongo container think they have 21GB of memory, so they try to use 80% of it
So the solution for me was to restart one of the container with a memory limit given to the mongo process :
--wiredTigerCacheSizeGB 7
The problem with that solution is that the limit is fixed for each mongo container. If one base needs more memory, I would have to restart the container with another value.
So please I have some questions. I think these questions might interest others in general, since I didn't find anything about that precisely on the Internet :
1) Is there a global solution to balance memory between mongo container?
That is, automatically? (without manual supervision, where I've got to check the I/O on disks)
And also, without restarting the container?
2) Are Cache limitations really useful?
Since the OS limits the container anyway, should I remove the limit and disable the alarms I get? (Not doing that anyway)
3) Is it really useful to have one container per base?
Would it be more practical, under the aspect of memory, to have one big mongo container for all three bases?
What would be the pros and cons for both solutions?
One mongo container for all projects bases
Pros:
Easier to manage
Easier to balance memory
Cons:
Less secure
One mongo container per base:
Pros:
More secure
Easier to backup? (not really)
Cons:
Difficult to handle memory
4) We are having a more general debate about how memory should relate to disk with mongo.
Personally, I don't think it's a problem if the base on disk is bigger than its footprint in memory, ie it's OK to have parts of database on disk that are rarely touched and thus won't find themselves in memory.
My devs think that size on disk should be the size in memory. That is, if I have a 40GB databases, I should have 40GB of memory, which appear unrealistic to me.
What is your opinion on that?
Thank you everyone for their answers!
mongodb docker memory-management
asked Nov 12 '18 at 14:53
BibeloBibelo
113
We have an apache/mongo architecture, organized around Docker. So far everything was fine, but with the bases growing, we now face new challenges.
Right now, we have 3 projects in production, with a total of 6 containers (1 apache container and 1 mongo container per project).
The problem we face is that each mongo container think they have 21GB of memory, so they try to use 80% of it
So the solution for me was to restart one of the container with a memory limit given to the mongo process :
--wiredTigerCacheSizeGB 7
The problem with that solution is that the limit is fixed for each mongo container. If one base needs more memory, I would have to restart the container with another value.
So please I have some questions. I think these questions might interest others in general, since I didn't find anything about that precisely on the Internet :
1) Is there a global solution to balance memory between mongo container?
That is, automatically? (without manual supervision, where I've got to check the I/O on disks)
And also, without restarting the container?
2) Are Cache limitations really useful?
Since the OS limits the container anyway, should I remove the limit and disable the alarms I get? (Not doing that anyway)
3) Is it really useful to have one container per base?
Would it be more practical, under the aspect of memory, to have one big mongo container for all three bases?
What would be the pros and cons for both solutions?
One mongo container for all projects bases
Pros:
Easier to manage
Easier to balance memory
Cons:
Less secure
One mongo container per base:
Pros:
More secure
Easier to backup? (not really)
Cons:
Difficult to handle memory
4) We are having a more general debate about how memory should relate to disk with mongo.
Personally, I don't think it's a problem if the base on disk is bigger than its footprint in memory, ie it's OK to have parts of database on disk that are rarely touched and thus won't find themselves in memory.
My devs think that size on disk should be the size in memory. That is, if I have a 40GB databases, I should have 40GB of memory, which appear unrealistic to me.
What is your opinion on that?
Thank you everyone for their answers!
mongodb docker memory-management
mongodb docker memory-management
asked Nov 12 '18 at 14:53
BibeloBibelo
113
asked Nov 12 '18 at 14:53
BibeloBibelo
113
edited Nov 12 '18 at 14:59
Bibelo
asked Nov 12 '18 at 14:53
BibeloBibelo
113
asked Nov 12 '18 at 14:53
BibeloBibelo
113
asked Nov 12 '18 at 14:53
BibeloBibelo
113
113
add a comment |
add a comment |
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