[Gluster-users] [Gluster-devel] Huge VSZ (VIRT) usage by glustershd on dummy node

[Oleksandr Natalenko]

I believe, multi-threaded shd has not been merged at least into 3.7 
branch prior to 3.7.11 (incl.), because I've found this [1].

[1] https://www.gluster.org/pipermail/maintainers/2016-April/000628.html

06.06.2016 12:21, Kaushal M написав:
> Has multi-threaded SHD been merged into 3.7.* by any chance? If not,
> what I'm saying below doesn't apply.
> 
> We saw problems when encrypted transports were used, because the RPC
> layer was not reaping threads (doing pthread_join) when a connection
> ended. This lead to similar observations of huge VIRT and relatively
> small RSS.
> 
> I'm not sure how multi-threaded shd works, but it could be leaking
> threads in a similar way.
> 
> On Mon, Jun 6, 2016 at 1:54 PM, Oleksandr Natalenko
> <oleksandr at natalenko.name> wrote:
>> Hello.
>> 
>> We use v3.7.11, replica 2 setup between 2 nodes + 1 dummy node for 
>> keeping
>> volumes metadata.
>> 
>> Now we observe huge VSZ (VIRT) usage by glustershd on dummy node:
>> 
>> ===
>> root     15109  0.0 13.7 76552820 535272 ?     Ssl  тра26   2:11
>> /usr/sbin/glusterfs -s localhost --volfile-id gluster/glustershd -p
>> /var/lib/glusterd/glustershd/run/glustershd.pid -l
>> /var/log/glusterfs/glustershd.log -S
>> /var/run/gluster/7848e17764dd4ba80f4623aecb91b07a.socket 
>> --xlator-option
>> *replicate*.node-uuid=80bc95e1-2027-4a96-bb66-d9c8ade624d7
>> ===
>> 
>> that is ~73G. RSS seems to be OK (~522M). Here is the statedump of
>> glustershd process: [1]
>> 
>> Also, here is sum of sizes, presented in statedump:
>> 
>> ===
>> # cat /var/run/gluster/glusterdump.15109.dump.1465200139 | awk -F '=' 
>> 'BEGIN
>> {sum=0} /^size=/ {sum+=$2} END {print sum}'
>> 353276406
>> ===
>> 
>> That is ~337 MiB.
>> 
>> Also, here are VIRT values from 2 replica nodes:
>> 
>> ===
>> root     24659  0.0  0.3 5645836 451796 ?      Ssl  тра24   3:28
>> /usr/sbin/glusterfs -s localhost --volfile-id gluster/glustershd -p
>> /var/lib/glusterd/glustershd/run/glustershd.pid -l
>> /var/log/glusterfs/glustershd.log -S
>> /var/run/gluster/44ec3f29003eccedf894865107d5db90.socket 
>> --xlator-option
>> *replicate*.node-uuid=a19afcc2-e26c-43ce-bca6-d27dc1713e87
>> root     18312  0.0  0.3 6137500 477472 ?      Ssl  тра19   6:37
>> /usr/sbin/glusterfs -s localhost --volfile-id gluster/glustershd -p
>> /var/lib/glusterd/glustershd/run/glustershd.pid -l
>> /var/log/glusterfs/glustershd.log -S
>> /var/run/gluster/1670a3abbd1eea968126eb6f5be20322.socket 
>> --xlator-option
>> *replicate*.node-uuid=52dca21b-c81c-48b5-9de2-1ed37987fbc2
>> ===
>> 
>> Those are 5 to 6G, which is much less than dummy node has, but still 
>> look
>> too big for us.
>> 
>> Should we care about huge VIRT value on dummy node? Also, how one 
>> would
>> debug that?
>> 
>> Regards,
>>   Oleksandr.
>> 
>> [1] https://gist.github.com/d2cfa25251136512580220fcdb8a6ce6
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