Re: question on mon memory usage

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Interesting script.

My Python process runs out of memory.  I'm wondering if I need to
increase the stack size or something.  Here's what I get when I run
the stock script:

# ./dump_proc_mem.py 29361 > monb_proc_mem.dump
PID = 29361
PASS :
00400000-006d3000 r-xp 00000000 09:02 139077
  /usr/bin/ceph-mon


PASS :
008d3000-008d8000 r--p 002d3000 09:02 139077
  /usr/bin/ceph-mon


OK :
008d8000-008de000 rw-p 002d8000 09:02 139077
  /usr/bin/ceph-mon

start = 9273344

OK :
008de000-01081000 rw-p 00000000 00:00 0

start = 9297920

OK :
02f70000-04bbb000 rw-p 00000000 00:00 0                                  [heap]

start = 49741824

OK :
04bbb000-5b621f000 rw-p 00000000 00:00 0                                 [heap]

start = 79409152
Traceback (most recent call last):
  File "./dump_proc_mem.py", line 27, in <module>
    chunk = mem_file.read(end - start)  # read region contents
MemoryError

It dies in the same place every time.
>From what I can tell of the script, it's going to try and read the
address space 04bbb000-5b621f000, all at once.  Which if my math is
correct, is the full 22GB.  =)  I'm modify the script now to read this
in 1MB chunks or so.

On Tue, Feb 26, 2013 at 1:17 AM, Sage Weil <sage@xxxxxxxxxxx> wrote:
> On Mon, 25 Feb 2013, Travis Rhoden wrote:
>> Hi Sage,
>>
>> I gave that script a try.  Interestingly, I ended up with a core file
>> from gdb itself.
>>
>> # file core
>> core: ELF 64-bit LSB core file x86-64, version 1 (SYSV), SVR4-style,
>> from 'gdb --batch --pid 29361 -ex dump memory
>> 29361-04bbb000-57bf58000.dump 0x04bbb00'
>>
>> So I think gdb crashed.  But before that happened, I did get 195M of
>> output.  However, I was expecting a full 20+ GBs.  Not sure if what I
>> generated can be of use or not.  If so, I can tar and compress it all
>> and place it somewhere useful if you like.  At it's current size, I
>> could host it in dropbox for you to pull down.  At 20GB (if that had
>> worked) I would need a place to scp it.
>
> Argh.  Try this:
>
> http://ceph.com/qa/dump_proc_mem.txt
>
> it takes one argument (the pid).. pipe it to a file, bzip2, and post
> somewhere.  Hopefully that'll do the trick...
>
> sage
>
>
>>
>>  - Travis
>>
>> On Mon, Feb 25, 2013 at 8:12 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>> > On Mon, 25 Feb 2013, Travis Rhoden wrote:
>> >> Right now everything is on a stock setup.   I believe that means no core file.
>> >>
>> >> root@ceph2:~# ulimit -c
>> >> 0
>> >>
>> >> Doh.  I don't see anything in the ceph init script that would increase
>> >> this for the ceph-* processes.  Which is probably a good thing, of
>> >> course.
>> >
>> > Can you try something like this to grab an image of the process memory?
>> >
>> > #!/bin/bash
>> > grep rw-p /proc/$1/maps | sed -n 's/^\([0-9a-f]*\)-\([0-9a-f]*\) .*$/\1 \2/p' | while read start stop; do gdb --batch --pid $1 -ex "dump memory $1-$start-$stop.dump 0x$start 0x$stop"; done
>> >
>> > (from http://stackoverflow.com/questions/12977179/reading-living-process-memory-without-interrupting-it-proc-kcore-is-an-option)
>> >
>> > THanks!
>> > sage
>> >
>> >
>> >
>> >
>> >
>> >>
>> >> On Mon, Feb 25, 2013 at 7:40 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>> >> > On Mon, 25 Feb 2013, Travis Rhoden wrote:
>> >> >> Joao,
>> >> >>
>> >> >> Happy to help if I can.  responses inline.
>> >> >>
>> >> >> On Mon, Feb 25, 2013 at 4:05 PM, Joao Eduardo Luis
>> >> >> <joao.luis@xxxxxxxxxxx> wrote:
>> >> >> > On 02/25/2013 07:59 PM, Travis Rhoden wrote:
>> >> >> >>
>> >> >> >> Hi folks,
>> >> >> >>
>> >> >> >> A question about memory usage by the Mon.  I have a cluster that is
>> >> >> >> being used exclusively for RBD (no CephFS/mds).  I have 5 mons, and
>> >> >> >> one is slowly but surely using a heck of a lot more memory than the
>> >> >> >> others:
>> >> >> >>
>> >> >> >> # for x in ceph{1..5}; do ssh $x 'ps aux | grep ceph-mon | grep -v grep';
>> >> >> >> done
>> >> >> >> root     31034  5.2  0.1 312116 75516 ?        Ssl  Feb14 881:51
>> >> >> >> /usr/bin/ceph-mon -i a --pid-file /var/run/ceph/mon.a.pid -c
>> >> >> >> /etc/ceph/ceph.conf
>> >> >> >> root     29361  4.8 53.9 22526128 22238080 ?   Ssl  Feb14 822:36
>> >> >> >> /usr/bin/ceph-mon -i b --pid-file /var/run/ceph/mon.b.pid -c
>> >> >> >> /tmp/ceph.conf.31144
>> >> >> >> root     28421  7.0  0.1 273608 88608 ?        Ssl  Feb20 516:48
>> >> >> >> /usr/bin/ceph-mon -i c --pid-file /var/run/ceph/mon.c.pid -c
>> >> >> >> /tmp/ceph.conf.10625
>> >> >> >> root     25876  4.8  0.1 240752 84048 ?        Ssl  Feb14 816:54
>> >> >> >> /usr/bin/ceph-mon -i d --pid-file /var/run/ceph/mon.d.pid -c
>> >> >> >> /tmp/ceph.conf.31537
>> >> >> >> root     24505  4.8  0.1 228720 79284 ?        Ssl  Feb14 818:14
>> >> >> >> /usr/bin/ceph-mon -i e --pid-file /var/run/ceph/mon.e.pid -c
>> >> >> >> /tmp/ceph.conf.31734
>> >> >> >>
>> >> >> >> As you can see, one is up over 20GB, while the others are < 100MB.
>> >> >> >>
>> >> >> >> Is this normal?  The box has plenty of RAM -- I'm wondering if this is
>> >> >> >> a memory leak, or if it's just slowly finding more things it can cache
>> >> >> >> and such.
>> >> >> >>
>> >> >> >
>> >> >> > Hi Travis,
>> >> >> >
>> >> >> > Which version are you running?
>> >> >> >
>> >> >> # ceph --version
>> >> >> ceph version 0.56.3 (6eb7e15a4783b122e9b0c85ea9ba064145958aa5)
>> >> >>
>> >> >> That's the case all around OSDs, mons, librbd clients, everything in my cluster
>> >> >> > This has been something that pops in the list every now and then, and I've
>> >> >> > spent a considerable amount of time trying to track it down.
>> >> >> >
>> >> >> > My current suspicion lies on the in-memory pgmap growing, and growing, and
>> >> >> > growing... and it usually hits the leader the worst.  Can you please confirm
>> >> >> > that mon.b is indeed the leader?
>> >> >> I'm not 100% sure how to do that.  I'm guessing rank 0 from the
>> >> >> following output?
>> >> >>
>> >> >> # ceph quorum_status
>> >> >> { "election_epoch": 32,
>> >> >>   "quorum": [
>> >> >>         0,
>> >> >>         1,
>> >> >>         2,
>> >> >>         3,
>> >> >>         4],
>> >> >>   "monmap": { "epoch": 1,
>> >> >>       "fsid": "d5229b51-5321-48d2-bbb2-16062abb1992",
>> >> >>       "modified": "2013-01-21 17:58:14.389411",
>> >> >>       "created": "2013-01-21 17:58:14.389411",
>> >> >>       "mons": [
>> >> >>             { "rank": 0,
>> >> >>               "name": "a",
>> >> >>               "addr": "10.10.30.1:6789\/0"},
>> >> >>             { "rank": 1,
>> >> >>               "name": "b",
>> >> >>               "addr": "10.10.30.2:6789\/0"},
>> >> >>             { "rank": 2,
>> >> >>               "name": "c",
>> >> >>               "addr": "10.10.30.3:6789\/0"},
>> >> >>             { "rank": 3,
>> >> >>               "name": "d",
>> >> >>               "addr": "10.10.30.4:6789\/0"},
>> >> >>             { "rank": 4,
>> >> >>               "name": "e",
>> >> >>               "addr": "10.10.30.5:6789\/0"}]}}
>> >> >>
>> >> >> That would seem to imply that mon a is the leader.  mon b is
>> >> >> definitely the problem child at the moment.
>> >> >>
>> >> >> I did a quick check, and mon b has grown by ~ 400MB since my previous
>> >> >> email.  So we're looking at a little under 100MB/hr, perhaps.  Not
>> >> >> sure if that's consistent or not.  WIll certainly check again in the
>> >> >> morning.
>> >> >
>> >> > Do you know if there is a core file ulimit set on that process?  If the
>> >> > core is configured to go somewhere, a kill -SEGV on it would generate a
>> >> > core that would help us figure out what the memory is consumed by.
>> >> >
>> >> > Thanks!
>> >> > sage
>> >> >
>> >>
>> >>
>>
>>
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