[Gluster-devel] Removing Fix layout during attach

[Joseph Fernandes]

Yep got it! A Cold tier may be running crippled but adding of a working hot tier need not bother about it.
But still there is a issue, The files in the offline cold-subvol will not be heal by the DB and hence when the cold-subvol comes online
the file will not be promoted or demote untill a named lookup heal happens on it. In this case should we
give a warning or message in the log about it.


----- Original Message -----
From: "Nithya Balachandran" <nbalacha at redhat.com>
To: "Joseph Fernandes" <josferna at redhat.com>
Cc: "Gluster Devel" <gluster-devel at gluster.org>, "Mohammed Rafi K C" <rkavunga at redhat.com>, rhgs-tiering at redhat.com
Sent: Tuesday, February 23, 2016 9:35:04 AM
Subject: Re: Removing Fix layout during attach


> Well as add brick to a normal volume do we have this constraint ?
> 

The add brick is a different scenario - regular DHT rebalance requires that all subvols be up. The same need not necessarily be the case for tiering.



> ----- Original Message -----
> From: "Nithya Balachandran" <nbalacha at redhat.com>
> To: "Joseph Fernandes" <josferna at redhat.com>
> Cc: "Gluster Devel" <gluster-devel at gluster.org>, "Mohammed Rafi K C"
> <rkavunga at redhat.com>, rhgs-tiering at redhat.com
> Sent: Monday, February 22, 2016 4:31:01 PM
> Subject: Re: Removing Fix layout during attach
> 
> > +gluster-devel
> > 
> > ----- Original Message -----
> > From: "Joseph Fernandes" <josferna at redhat.com>
> > To: "Mohammed Rafi K C" <rkavunga at redhat.com>
> > Cc: "Nithya Balachandran" <nbalacha at redhat.com>, rhgs-tiering at redhat.com
> > Sent: Monday, February 22, 2016 4:21:48 PM
> > Subject: Re: Removing Fix layout during attach
> > 
> > Thanks Rafi for the follow up mail after the call.
> > 
> > 1. Yep first we will have a background fixlayout which will serve two
> > things
> >    a. Proactive healing of directories so that the first io need not do it.
> >    b. CTR Database heal using lookups.
> > 
> > 2. The race (https://bugzilla.redhat.com/show_bug.cgi?id=1286208.) is the
> > view consistency issue of gluster and will happen anyhow.
> > 
> > Regards,
> > Joe
> 
> 
> Something else that can be considered - does the tier daemon really require
> all subvols to be up?
> 
> > 
> > 
> > ----- Original Message -----
> > From: "Mohammed Rafi K C" <rkavunga at redhat.com>
> > To: "Joseph Fernandes" <josferna at redhat.com>, "Nithya Balachandran"
> > <nbalacha at redhat.com>
> > Cc: rhgs-tiering at redhat.com
> > Sent: Monday, February 22, 2016 4:13:17 PM
> > Subject: Re: Removing Fix layout during attach
> > 
> > 
> > 
> > On 02/22/2016 12:24 PM, Joseph Fernandes wrote:
> > > Hi Nithya/Rafi,
> > >
> > > Could you please let me know what are the implication of not having fix
> > > layout during attach tier.
> > 
> > One of the major problem is the performance drop, can be neutralized by
> > having a background fix-layout. Again if we are planning to have a
> > background fix-layout, though it is independent of tier functionality it
> > is good to have a way to determine whether we completed a successful
> > fix-layout at least once, if so we don't need to run fix-layout for
> > every tier restart.
> > 
> > Currently tier daemon will be killed if fix-layout fails, I think we can
> > remove this constrain. We can abort the back ground fix-layout, but in
> > my understanding we don't need to stop the tier process.
> > 
> > >
> > > I am looking into this issue now and would like to know what are prior
> > > discussion that happened before. Just getting insync.
> > This is the one of the open bug [1] that I'm aware of, which can hit in
> > this case. But this race is independent of tier and fix-layout all
> > together. So we can move forward , and this can be fixed parallel.
> > 
> > [1] : https://bugzilla.redhat.com/show_bug.cgi?id=1286208.
> > 
> > Regards!
> > Rafi KC
> > 
> > >
> > > Regards,
> > > Joe
> > 
> > 
>