[Gluster-devel] gluster source code help
ravishankar at redhat.com
Fri Feb 3 11:58:09 UTC 2017
On 02/03/2017 09:14 AM, jayakrishnan mm wrote:
> On Thu, Feb 2, 2017 at 8:17 PM, Ravishankar N <ravishankar at redhat.com
> <mailto:ravishankar at redhat.com>> wrote:
> On 02/02/2017 10:46 AM, jayakrishnan mm wrote:
>> 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
> 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.
> Best regards
>> Best regards
>> Gluster-devel mailing list
>> Gluster-devel at gluster.org <mailto:Gluster-devel at gluster.org>
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