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

[Kaushal M]

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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