On 02/06/2017 03:15 PM, jayakrishnan mm wrote:
On Mon, Feb 6, 2017 at 2:36 PM, jayakrishnan mm
<[email protected] <mailto:[email protected]>> wrote:
On Fri, Feb 3, 2017 at 7:58 PM, Ravishankar N
<[email protected] <mailto:[email protected]>> wrote:
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.
Hi Ravi,
The self heal daemon searches in .glusterfs/indices/xattrop
directory for the files/dirs to be healed . Who is updating this
information , and on what basis ?
Please see
https://github.com/gluster/glusterfs-specs/blob/master/done/Features/afr-v1.md,
it is a bit dated (relevant to AFR v1, which is in glusterfs 3.5 and
older I think) but the concepts are similar. The entries are
added/removed by the index translator during the pre-op/post-op phases
of the AFR transaction .
Thanks Ravi, for the explanation.
Regards
JK
Regards,
Ravi
Thanks
Best regards
Best regards
JK
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