Fwd: NFS and Memory Buffers

Fwd: NFS and Memory Buffers

[Pablo Silva]

Dear Readers:

     My boss has entrusted me to analyze why the memory buffers are
not released a Linux server with Centos 6.4.?

    As informs me, the current reading is:


[root@bck ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         15936      15788        147          0       6746        438
-/+ buffers/cache:       8604       7332
Swap:         2047          0       2047
[root@bck ~]#
[root@bck ~]#
[root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
restart && free -m
Stopping snmpd:                                            [  OK  ]
Starting snmpd:                                            [  OK  ]
             total       used       free     shared    buffers     cached
Mem:         15936        509      15426          0         93         16
-/+ buffers/cache:        400      15536
Swap:         2047          0       2047
[root@bck ~]#

   I can not find the solution to release the memory buffer and cache
memory so grateful for any hint for finding the solution to this
"problem".

-Paul

Re: Fwd: NFS and Memory Buffers

[Benjamin Coddington]

Dear Pablo,

	Why are you restarting snmpd between flushing cache and reading
memory values?  On a running system you can probably expect the
cache to immediately start to fill after a flush anyway.
y
Ben

On Mon, 15 Dec 2014, Pablo Silva wrote:

> Dear Readers:
>
>      My boss has entrusted me to analyze why the memory buffers are
> not released a Linux server with Centos 6.4.?
>
>     As informs me, the current reading is:
>
>
> [root@bck ~]# free -m
>              total       used       free     shared    buffers     cached
> Mem:         15936      15788        147          0       6746        438
> -/+ buffers/cache:       8604       7332
> Swap:         2047          0       2047
> [root@bck ~]#
> [root@bck ~]#
> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
> restart && free -m
> Stopping snmpd:                                            [  OK  ]
> Starting snmpd:                                            [  OK  ]
>              total       used       free     shared    buffers     cached
> Mem:         15936        509      15426          0         93         16
> -/+ buffers/cache:        400      15536
> Swap:         2047          0       2047
> [root@bck ~]#
>
>    I can not find the solution to release the memory buffer and cache
> memory so grateful for any hint for finding the solution to this
> "problem".
>
> -Paul
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: Fwd: NFS and Memory Buffers

[Trond Myklebust]

On Mon, Dec 15, 2014 at 7:52 AM, Benjamin Coddington
<bcodding@redhat.com> wrote:
> Dear Pablo,
>
>         Why are you restarting snmpd between flushing cache and reading
> memory values?  On a running system you can probably expect the
> cache to immediately start to fill after a flush anyway.
> y
> Ben
>
> On Mon, 15 Dec 2014, Pablo Silva wrote:
>
>> Dear Readers:
>>
>>      My boss has entrusted me to analyze why the memory buffers are
>> not released a Linux server with Centos 6.4.?
>>
>>     As informs me, the current reading is:
>>
>>
>> [root@bck ~]# free -m
>>              total       used       free     shared    buffers     cached
>> Mem:         15936      15788        147          0       6746        438
>> -/+ buffers/cache:       8604       7332
>> Swap:         2047          0       2047
>> [root@bck ~]#
>> [root@bck ~]#
>> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
>> restart && free -m
>> Stopping snmpd:                                            [  OK  ]
>> Starting snmpd:                                            [  OK  ]
>>              total       used       free     shared    buffers     cached
>> Mem:         15936        509      15426          0         93         16
>> -/+ buffers/cache:        400      15536
>> Swap:         2047          0       2047
>> [root@bck ~]#
>>
>>    I can not find the solution to release the memory buffer and cache
>> memory so grateful for any hint for finding the solution to this
>> "problem".
>>
>> -Paul
>>

See the top entry on googling "why does linux cache memory":
http://www.linuxatemyram.com/


-- 
Trond Myklebust

Linux NFS client maintainer, PrimaryData

trond.myklebust@primarydata.com

Re: Fwd: NFS and Memory Buffers

[Pablo Silva]

Dear Benajmin;

     A colleague sent me this information as is, but the curious thing
which does not release the memory buffer, except using the commands
that you can appreciate.

I am investigating if possible "know" that information is being stored
there, and from what I see there is a command linux-fTools that could
help me descubir the information being stored there, do not know if I
bring in my analysis but it is my first step, I do not know if you
have any other suggestions.

grateful

- Pablo

On Mon, Dec 15, 2014 at 9:52 AM, Benjamin Coddington
<bcodding@redhat.com> wrote:
> Dear Pablo,
>
>         Why are you restarting snmpd between flushing cache and reading
> memory values?  On a running system you can probably expect the
> cache to immediately start to fill after a flush anyway.
> y
> Ben
>
> On Mon, 15 Dec 2014, Pablo Silva wrote:
>
>> Dear Readers:
>>
>>      My boss has entrusted me to analyze why the memory buffers are
>> not released a Linux server with Centos 6.4.?
>>
>>     As informs me, the current reading is:
>>
>>
>> [root@bck ~]# free -m
>>              total       used       free     shared    buffers     cached
>> Mem:         15936      15788        147          0       6746        438
>> -/+ buffers/cache:       8604       7332
>> Swap:         2047          0       2047
>> [root@bck ~]#
>> [root@bck ~]#
>> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
>> restart && free -m
>> Stopping snmpd:                                            [  OK  ]
>> Starting snmpd:                                            [  OK  ]
>>              total       used       free     shared    buffers     cached
>> Mem:         15936        509      15426          0         93         16
>> -/+ buffers/cache:        400      15536
>> Swap:         2047          0       2047
>> [root@bck ~]#
>>
>>    I can not find the solution to release the memory buffer and cache
>> memory so grateful for any hint for finding the solution to this
>> "problem".
>>
>> -Paul
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>

Re: Fwd: NFS and Memory Buffers

[Pablo Silva]

Hi Trond!

     Yes, i've just to read this web page, but my boss is afraid to
make swapping to continue growing consumption of buffer memory, if it
is true, linux should be responsible for its administration ignored
the reason to emphasize tuning the memory consumption.


-Pablo

On Mon, Dec 15, 2014 at 9:57 AM, Trond Myklebust
<trond.myklebust@primarydata.com> wrote:
> On Mon, Dec 15, 2014 at 7:52 AM, Benjamin Coddington
> <bcodding@redhat.com> wrote:
>> Dear Pablo,
>>
>>         Why are you restarting snmpd between flushing cache and reading
>> memory values?  On a running system you can probably expect the
>> cache to immediately start to fill after a flush anyway.
>> y
>> Ben
>>
>> On Mon, 15 Dec 2014, Pablo Silva wrote:
>>
>>> Dear Readers:
>>>
>>>      My boss has entrusted me to analyze why the memory buffers are
>>> not released a Linux server with Centos 6.4.?
>>>
>>>     As informs me, the current reading is:
>>>
>>>
>>> [root@bck ~]# free -m
>>>              total       used       free     shared    buffers     cached
>>> Mem:         15936      15788        147          0       6746        438
>>> -/+ buffers/cache:       8604       7332
>>> Swap:         2047          0       2047
>>> [root@bck ~]#
>>> [root@bck ~]#
>>> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
>>> restart && free -m
>>> Stopping snmpd:                                            [  OK  ]
>>> Starting snmpd:                                            [  OK  ]
>>>              total       used       free     shared    buffers     cached
>>> Mem:         15936        509      15426          0         93         16
>>> -/+ buffers/cache:        400      15536
>>> Swap:         2047          0       2047
>>> [root@bck ~]#
>>>
>>>    I can not find the solution to release the memory buffer and cache
>>> memory so grateful for any hint for finding the solution to this
>>> "problem".
>>>
>>> -Paul
>>>
>
> See the top entry on googling "why does linux cache memory":
> http://www.linuxatemyram.com/
>
>
> --
> Trond Myklebust
>
> Linux NFS client maintainer, PrimaryData
>
> trond.myklebust@primarydata.com

Re: Fwd: NFS and Memory Buffers

[Benjamin Coddington]

What you're doing does result in the cache being flushed, only to
immediately start to fill again.

I should have replied more to the point as Trond did: this is normal, do
not worry.  Your memory is not being "used up", as the cache memory is given
back to the system if it is needed for other use.

Ben

On Mon, 15 Dec 2014, Pablo Silva wrote:

> Dear Benajmin;
>
>      A colleague sent me this information as is, but the curious thing
> which does not release the memory buffer, except using the commands
> that you can appreciate.
>
> I am investigating if possible "know" that information is being stored
> there, and from what I see there is a command linux-fTools that could
> help me descubir the information being stored there, do not know if I
> bring in my analysis but it is my first step, I do not know if you
> have any other suggestions.
>
> grateful
>
> - Pablo
>
> On Mon, Dec 15, 2014 at 9:52 AM, Benjamin Coddington
> <bcodding@redhat.com> wrote:
> > Dear Pablo,
> >
> >         Why are you restarting snmpd between flushing cache and reading
> > memory values?  On a running system you can probably expect the
> > cache to immediately start to fill after a flush anyway.
> > y
> > Ben
> >
> > On Mon, 15 Dec 2014, Pablo Silva wrote:
> >
> >> Dear Readers:
> >>
> >>      My boss has entrusted me to analyze why the memory buffers are
> >> not released a Linux server with Centos 6.4.?
> >>
> >>     As informs me, the current reading is:
> >>
> >>
> >> [root@bck ~]# free -m
> >>              total       used       free     shared    buffers     cached
> >> Mem:         15936      15788        147          0       6746        438
> >> -/+ buffers/cache:       8604       7332
> >> Swap:         2047          0       2047
> >> [root@bck ~]#
> >> [root@bck ~]#
> >> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
> >> restart && free -m
> >> Stopping snmpd:                                            [  OK  ]
> >> Starting snmpd:                                            [  OK  ]
> >>              total       used       free     shared    buffers     cached
> >> Mem:         15936        509      15426          0         93         16
> >> -/+ buffers/cache:        400      15536
> >> Swap:         2047          0       2047
> >> [root@bck ~]#
> >>
> >>    I can not find the solution to release the memory buffer and cache
> >> memory so grateful for any hint for finding the solution to this
> >> "problem".
> >>
> >> -Paul
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>
>

Re: Fwd: NFS and Memory Buffers

[Pablo Silva]

Thanks Benjamin for your comment, well ..

After the memory buffer is released, my Boos and colleague OpenNMS
observed by passing a time period and is refilled, and therefore an
alarm is triggered indicating opennms:

Low threshold exceeded for SNMP datasource (memAvailReal + memcached)
/ memTotalReal * 100.0 interface on 172.16.10.37, parms: label =
"Unknown" ds = "(memAvailReal + memcached) / memTotalReal * 100.0"
value = "4.65" instance = "null "instanceLabel =" null "resourceId ="
node [799] .nodeSnmp [] "trigger =" 2 "rearm =" 10.0 "threshold =" 5.0
"

I have the graphic, but could send tinypic, if the list to send
messages with pictures.

Doubt my Boss is why the buffer memory is not released and growing
without anything to release him unless use of the commands that I sent
is made.

The only service that is running there is NFS, which uses the default settings.

[root @ bck ~] # cat / etc / exports
/ backup * (rw, sync)
/ BACKUP / RESPALDO01 172.16.30.4 (rw, insecure, sync, no_wdelay,
no_root_squash)

 I told them that's no problem using buffer memory, and it is natural
that Linux consumes memory and administer, but my Boss on reason not
automatically releases the buffer memory persists.

The current reading is:

[root@bck ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         15936      15748        188          0       4095      10770
-/+ buffers/cache:        881      15055
Swap:         2047          0       2047
[root@bck ~]#


  -Pablo

On Mon, Dec 15, 2014 at 10:08 AM, Benjamin Coddington
<bcodding@redhat.com> wrote:
> What you're doing does result in the cache being flushed, only to
> immediately start to fill again.
>
> I should have replied more to the point as Trond did: this is normal, do
> not worry.  Your memory is not being "used up", as the cache memory is given
> back to the system if it is needed for other use.
>
> Ben
>
> On Mon, 15 Dec 2014, Pablo Silva wrote:
>
>> Dear Benajmin;
>>
>>      A colleague sent me this information as is, but the curious thing
>> which does not release the memory buffer, except using the commands
>> that you can appreciate.
>>
>> I am investigating if possible "know" that information is being stored
>> there, and from what I see there is a command linux-fTools that could
>> help me descubir the information being stored there, do not know if I
>> bring in my analysis but it is my first step, I do not know if you
>> have any other suggestions.
>>
>> grateful
>>
>> - Pablo
>>
>> On Mon, Dec 15, 2014 at 9:52 AM, Benjamin Coddington
>> <bcodding@redhat.com> wrote:
>> > Dear Pablo,
>> >
>> >         Why are you restarting snmpd between flushing cache and reading
>> > memory values?  On a running system you can probably expect the
>> > cache to immediately start to fill after a flush anyway.
>> > y
>> > Ben
>> >
>> > On Mon, 15 Dec 2014, Pablo Silva wrote:
>> >
>> >> Dear Readers:
>> >>
>> >>      My boss has entrusted me to analyze why the memory buffers are
>> >> not released a Linux server with Centos 6.4.?
>> >>
>> >>     As informs me, the current reading is:
>> >>
>> >>
>> >> [root@bck ~]# free -m
>> >>              total       used       free     shared    buffers     cached
>> >> Mem:         15936      15788        147          0       6746        438
>> >> -/+ buffers/cache:       8604       7332
>> >> Swap:         2047          0       2047
>> >> [root@bck ~]#
>> >> [root@bck ~]#
>> >> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
>> >> restart && free -m
>> >> Stopping snmpd:                                            [  OK  ]
>> >> Starting snmpd:                                            [  OK  ]
>> >>              total       used       free     shared    buffers     cached
>> >> Mem:         15936        509      15426          0         93         16
>> >> -/+ buffers/cache:        400      15536
>> >> Swap:         2047          0       2047
>> >> [root@bck ~]#
>> >>
>> >>    I can not find the solution to release the memory buffer and cache
>> >> memory so grateful for any hint for finding the solution to this
>> >> "problem".
>> >>
>> >> -Paul
>> >> --
>> >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> >> the body of a message to majordomo@vger.kernel.org
>> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> >>
>>

Re: Fwd: NFS and Memory Buffers

[Benjamin Coddington]

I think your question is "why is the memory not automatically released?"
It is not being released because nothing else requires the use of that
memory.

Ben

On Mon, 15 Dec 2014, Pablo Silva wrote:

> Thanks Benjamin for your comment, well ..
>
> After the memory buffer is released, my Boos and colleague OpenNMS
> observed by passing a time period and is refilled, and therefore an
> alarm is triggered indicating opennms:
>
> Low threshold exceeded for SNMP datasource (memAvailReal + memcached)
> / memTotalReal * 100.0 interface on 172.16.10.37, parms: label =
> "Unknown" ds = "(memAvailReal + memcached) / memTotalReal * 100.0"
> value = "4.65" instance = "null "instanceLabel =" null "resourceId ="
> node [799] .nodeSnmp [] "trigger =" 2 "rearm =" 10.0 "threshold =" 5.0
> "
>
> I have the graphic, but could send tinypic, if the list to send
> messages with pictures.
>
> Doubt my Boss is why the buffer memory is not released and growing
> without anything to release him unless use of the commands that I sent
> is made.
>
> The only service that is running there is NFS, which uses the default settings.
>
> [root @ bck ~] # cat / etc / exports
> / backup * (rw, sync)
> / BACKUP / RESPALDO01 172.16.30.4 (rw, insecure, sync, no_wdelay,
> no_root_squash)
>
>  I told them that's no problem using buffer memory, and it is natural
> that Linux consumes memory and administer, but my Boss on reason not
> automatically releases the buffer memory persists.
>
> The current reading is:
>
> [root@bck ~]# free -m
>              total       used       free     shared    buffers     cached
> Mem:         15936      15748        188          0       4095      10770
> -/+ buffers/cache:        881      15055
> Swap:         2047          0       2047
> [root@bck ~]#
>
>
>   -Pablo
>
> On Mon, Dec 15, 2014 at 10:08 AM, Benjamin Coddington
> <bcodding@redhat.com> wrote:
> > What you're doing does result in the cache being flushed, only to
> > immediately start to fill again.
> >
> > I should have replied more to the point as Trond did: this is normal, do
> > not worry.  Your memory is not being "used up", as the cache memory is given
> > back to the system if it is needed for other use.
> >
> > Ben
> >
> > On Mon, 15 Dec 2014, Pablo Silva wrote:
> >
> >> Dear Benajmin;
> >>
> >>      A colleague sent me this information as is, but the curious thing
> >> which does not release the memory buffer, except using the commands
> >> that you can appreciate.
> >>
> >> I am investigating if possible "know" that information is being stored
> >> there, and from what I see there is a command linux-fTools that could
> >> help me descubir the information being stored there, do not know if I
> >> bring in my analysis but it is my first step, I do not know if you
> >> have any other suggestions.
> >>
> >> grateful
> >>
> >> - Pablo
> >>
> >> On Mon, Dec 15, 2014 at 9:52 AM, Benjamin Coddington
> >> <bcodding@redhat.com> wrote:
> >> > Dear Pablo,
> >> >
> >> >         Why are you restarting snmpd between flushing cache and reading
> >> > memory values?  On a running system you can probably expect the
> >> > cache to immediately start to fill after a flush anyway.
> >> > y
> >> > Ben
> >> >
> >> > On Mon, 15 Dec 2014, Pablo Silva wrote:
> >> >
> >> >> Dear Readers:
> >> >>
> >> >>      My boss has entrusted me to analyze why the memory buffers are
> >> >> not released a Linux server with Centos 6.4.?
> >> >>
> >> >>     As informs me, the current reading is:
> >> >>
> >> >>
> >> >> [root@bck ~]# free -m
> >> >>              total       used       free     shared    buffers     cached
> >> >> Mem:         15936      15788        147          0       6746        438
> >> >> -/+ buffers/cache:       8604       7332
> >> >> Swap:         2047          0       2047
> >> >> [root@bck ~]#
> >> >> [root@bck ~]#
> >> >> [root@bck ~]# echo 3 > /proc/sys/vm/drop_caches && service snmpd
> >> >> restart && free -m
> >> >> Stopping snmpd:                                            [  OK  ]
> >> >> Starting snmpd:                                            [  OK  ]
> >> >>              total       used       free     shared    buffers     cached
> >> >> Mem:         15936        509      15426          0         93         16
> >> >> -/+ buffers/cache:        400      15536
> >> >> Swap:         2047          0       2047
> >> >> [root@bck ~]#
> >> >>
> >> >>    I can not find the solution to release the memory buffer and cache
> >> >> memory so grateful for any hint for finding the solution to this
> >> >> "problem".
> >> >>
> >> >> -Paul
> >> >> --
> >> >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> >> >> the body of a message to majordomo@vger.kernel.org
> >> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> >>
> >>
>