On 02/03/2017 09:14 AM, jayakrishnan mm wrote:
On Thu, Feb 2, 2017 at 8:17 PM, Ravishankar N <[email protected]
<mailto:[email protected]>> wrote:
On 02/02/2017 10:46 AM, jayakrishnan mm wrote:
Hi
How do I determine, which part of the code is run on the
client, and which part of the code is run on the server nodes by
merely looking at the the glusterfs source code ?
I knew there are client side and server side translators which
will run on respective platforms. I am looking at part of self
heal daemon source (ec/afr) which will run on the server nodes
and the part which run on the clients.
The self-heal daemon that runs on the server is also a client
process in the sense that it has client side xlators like ec or
afr and protocol/client (see the shd volfile
'glustershd-server.vol') loaded and talks to the bricks like a
normal client does.
The difference is that only self-heal related 'logic' get executed
on the shd while both self-heal and I/O related logic get executed
from the mount. The self-heal logic resides mostly in
afr-self-heal*.[ch] while I/O related logic is there in the other
files.
HTH,
Ravi
Hi JK,
Dear Ravi,
Thanks for your kind explanation.
So, each server node will have a separate self-heal daemon(shd) up and
running , every time a child_up event occurs, and this will be an
index healer.
And each daemon will spawn "priv->child_count " number of threads on
each server node . correct ?
shd is always running and yes those many threads are spawned for index
heal when the process starts.
1. When exactly a full healer spawns threads?
Whenever you run `gluster volume heal volname full`. See afr_xl_op().
There are some bugs in launching full heal though.
2. When can GF_EVENT_TRANSLATOR_OP & GF_SHD_OP_HEAL_INDEX happen
together (so that index healer spawns thread) ?
similarly when can GF_EVENT_TRANSLATOR_OP & GF_SHD_OP_HEAL_FULL
happen ? During replace-brick ?
Is it possible that index healer and full healer spawns threads
together (so that total number of threads is 2*priv->child_count)?
index heal threads wake up and run once every 10 minutes or whatever the
cluster.heal-timeout is. They are also run when a brick comes up like
you said, via afr_notify(). It is also run when you manually launch
'gluster volume heal volname`. Again see afr_xl_op().
3. In /var/lib/glusterd/glustershd/glustershd-server.vol , why
debug/io-stats is chosen as the top xlator ?
io-stats is generally loaded as the top most xlator in all graphs at the
appropriate place for gathering profile-info, but for shd, I'm not sure
if it has any specific use other than acting as a placeholder as a
parent to all replica xlators.
Regards,
Ravi
Thanks
Best regards
Best regards
JK
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