[Gluster-devel] Question on merging zfs snapshot support into the mainline glusterfs
Avra Sengupta
asengupt at redhat.com
Mon Sep 19 17:28:47 UTC 2016
Hi Sriram,
I have created a bug for this
(https://bugzilla.redhat.com/show_bug.cgi?id=1377437). The plan is that
for the first patch as mentioned below, let's not meddle with the zfs
code at all. What we are looking at is segregating the lvm based code as
is today, from the management infrastructure (which is addressed in your
patch), and creating a table based pluggable infra(refer to
gd_svc_cli_actors[] in xlators/mgmt/glusterd/src/glusterd-handler.c and
other similar tables in gluster code base to get a understanding of what
I am conveying), which can be used to call this code and still achieve
the same results as we do today.
Once this code is merged, we can use the same infra to start pushing in
the zfs code (rest of your current patch). Please let me know if you
have further queries regarding this. Thanks.
Regards,
Avra
On 09/19/2016 07:52 PM, sriram at marirs.net.in wrote:
> Hi Avra,
>
> Do you have a bug id for this changes? Or may I raise a new one?
>
> Sriram
>
>
> On Fri, Sep 16, 2016, at 11:37 AM, sriram at marirs.net.in
> <mailto:sriram at marirs.net.in> wrote:
>> Thanks Avra,
>>
>> I'll send this patch to gluster master in a while.
>>
>> Sriram
>>
>>
>> On Wed, Sep 14, 2016, at 03:08 PM, Avra Sengupta wrote:
>>> Hi Sriram,
>>>
>>> Sorry for the delay in response. I started going through the commits
>>> in the github repo. I finished going through the first commit, where
>>> you create a plugin structure and move code. Following is the commit
>>> link:
>>>
>>> https://github.com/sriramster/glusterfs/commit/7bf157525539541ebf0aa36a380bbedb2cae5440
>>>
>>> FIrst of all, the overall approach of using plugins, and maintaining
>>> plugins that is used in the patch is in sync with what we had
>>> discussed. There are some gaps though, like in the zfs functions the
>>> snap brick is mounted without updating labels, and in restore you
>>> perform a zfs rollback, which significantly changes the behavior
>>> between how a lvm based snapshot and a zfs based snapshot.
>>>
>>> But before we get into these details, I would request you to kindly
>>> send this particular patch to the gluster master branch, as that is
>>> how we formally review patches, and I would say this particular
>>> patch in itself is ready for a formal review. Once we straighten out
>>> the quirks in this patch, we can significantly start moving the
>>> other dependent patches to master and reviewing them. Thanks.
>>>
>>> Regards,
>>> Avra
>>>
>>> P.S : Adding gluster-devel
>>>
>>> On 09/13/2016 01:14 AM, sriram at marirs.net.in
>>> <mailto:sriram at marirs.net.in> wrote:
>>>> Hi Avra,
>>>>
>>>> You'd time to look into the below request?
>>>>
>>>> Sriram
>>>>
>>>>
>>>> On Thu, Sep 8, 2016, at 01:20 PM, sriram at marirs.net.in
>>>> <mailto:sriram at marirs.net.in> wrote:
>>>>> Hi Avra,
>>>>>
>>>>> Thank you. Please, let me know your feedback. It would be helpful
>>>>> on continuing from then.
>>>>>
>>>>> Sriram
>>>>>
>>>>>
>>>>> On Thu, Sep 8, 2016, at 01:18 PM, Avra Sengupta wrote:
>>>>>> Hi Sriram,
>>>>>>
>>>>>> Rajesh is on a vacation, and will be available towards the end of
>>>>>> next week. He will be sharing his feedback once he is back.
>>>>>> Meanwhile I will have a look at the patch and share my feedback
>>>>>> with you. But it will take me some time to go through it. Thanks.
>>>>>>
>>>>>> Regards,
>>>>>> Avra
>>>>>>
>>>>>> On 09/08/2016 01:09 PM, sriram at marirs.net.in
>>>>>> <mailto:sriram at marirs.net.in> wrote:
>>>>>>> Hello Rajesh,
>>>>>>>
>>>>>>> Sorry to bother. Could you have a look at the below request?
>>>>>>>
>>>>>>> Sriram
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Sep 6, 2016, at 11:27 AM, sriram at marirs.net.in
>>>>>>> <mailto:sriram at marirs.net.in> wrote:
>>>>>>>> Hello Rajesh,
>>>>>>>>
>>>>>>>> Sorry for the delayed mail, was on leave. Could you let me know
>>>>>>>> the feedback?
>>>>>>>>
>>>>>>>> Sriram
>>>>>>>>
>>>>>>>>
>>>>>>>> On Fri, Sep 2, 2016, at 10:08 AM, Rajesh Joseph wrote:
>>>>>>>>> + Avra
>>>>>>>>> Hi Srirram,
>>>>>>>>>
>>>>>>>>> Sorry, I was on leave therefore could not reply.
>>>>>>>>> Added Avra who is also working on the snapshot component for
>>>>>>>>> review.
>>>>>>>>> Will take a look at your changes today.
>>>>>>>>> Thanks & Regards,
>>>>>>>>> Rajesh
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Thu, Sep 1, 2016 at 1:22 PM, <sriram at marirs.net.in
>>>>>>>>> <mailto:sriram at marirs.net.in>> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Hello Rajesh,
>>>>>>>>>
>>>>>>>>> Could you've a look at the below request?
>>>>>>>>>
>>>>>>>>> Sriram
>>>>>>>>>
>>>>>>>>> On Tue, Aug 30, 2016, at 01:03 PM, sriram at marirs.net.in
>>>>>>>>> <mailto:sriram at marirs.net.in> wrote:
>>>>>>>>>> Hi Rajesh,
>>>>>>>>>>
>>>>>>>>>> Continuing from the discussion we've had below and
>>>>>>>>>> suggestions made by you, had created a plugin like
>>>>>>>>>> structure (A generic plugin model) and added snapshot to
>>>>>>>>>> be the first plugin implementation. Could you've a look
>>>>>>>>>> if the approach is fine? I've not raised a official
>>>>>>>>>> review request yet. Could you give an initial review of
>>>>>>>>>> the model?
>>>>>>>>>>
>>>>>>>>>> https://github.com/sriramster/glusterfs/tree/sriram_dev
>>>>>>>>>>
>>>>>>>>>> Things done,
>>>>>>>>>>
>>>>>>>>>> - Created a new folder for glusterd plugins and added
>>>>>>>>>> snapshot as a plugin. Like this,
>>>>>>>>>>
>>>>>>>>>> $ROOT/xlators/mgmt/glusterd/plugins +
>>>>>>>>>> |
>>>>>>>>>> + __ snapshot/src
>>>>>>>>>>
>>>>>>>>>> Moved LVM related snapshot implementation to
>>>>>>>>>> xlators/mgmt/glusterd/plugins/snapshot/src/lvm-snapshot.c
>>>>>>>>>>
>>>>>>>>>> - Mostly isolated, glusterd code from snapshot
>>>>>>>>>> implementation by using logging, error codes and messages
>>>>>>>>>> from glusterd and libglusterfs.
>>>>>>>>>> - This way, i though we could get complete isolation of
>>>>>>>>>> snapshot plugin implementation which avoids most of
>>>>>>>>>> compiler and linking dependency issues.
>>>>>>>>>> - Created a library of the above like libgsnapshot.so and
>>>>>>>>>> linking it with glusterd.so to get this working.
>>>>>>>>>> - The complete isolation also makes us to avoid reverse
>>>>>>>>>> dependency like some api's inside plugin/snapshot being
>>>>>>>>>> dependent on glusterd.so
>>>>>>>>>>
>>>>>>>>>> TODO's :
>>>>>>>>>>
>>>>>>>>>> - Need to create glusterd_snapshot_ops structure which
>>>>>>>>>> would be used to register snapshot related API's with
>>>>>>>>>> glusterd.so.
>>>>>>>>>> - Add command line snapshot plugin option, so that it
>>>>>>>>>> picks up on compilation.
>>>>>>>>>> - If any missed implementation for plugin.
>>>>>>>>>> - Cleanup and get a review ready branch.
>>>>>>>>>>
>>>>>>>>>> Let me know if this looks ok? Or need to any more into
>>>>>>>>>> the list.
>>>>>>>>>>
>>>>>>>>>> Sriram
>>>>>>>>>>
>>>>>>>>>> On Fri, Jul 22, 2016, at 02:43 PM, Rajesh Joseph wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Jul 21, 2016 at 3:07 AM, Vijay Bellur
>>>>>>>>>>> <vbellur at redhat.com <mailto:vbellur at redhat.com>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> On 07/19/2016 11:01 AM, Atin Mukherjee wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Tue, Jul 19, 2016 at 7:29 PM, Rajesh Joseph
>>>>>>>>>>> <rjoseph at redhat.com <mailto:rjoseph at redhat.com>
>>>>>>>>>>> <mailto:rjoseph at redhat.com
>>>>>>>>>>> <mailto:rjoseph at redhat.com>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Tue, Jul 19, 2016 at 11:23 AM,
>>>>>>>>>>> <sriram at marirs.net.in <mailto:sriram at marirs.net.in>
>>>>>>>>>>> <mailto:sriram at marirs.net.in
>>>>>>>>>>> <mailto:sriram at marirs.net.in>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> __
>>>>>>>>>>> Hi Rajesh,
>>>>>>>>>>>
>>>>>>>>>>> I'd thought about moving the zfs specific
>>>>>>>>>>> implementation to
>>>>>>>>>>> something like
>>>>>>>>>>>
>>>>>>>>>>> xlators/mgmt/glusterd/src/plugins/zfs-specifs-stuffs
>>>>>>>>>>> for the
>>>>>>>>>>> inital go. Could you let me know if this works
>>>>>>>>>>> or in sync with
>>>>>>>>>>> what you'd thought about?
>>>>>>>>>>>
>>>>>>>>>>> Sriram
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Hi Sriram,
>>>>>>>>>>>
>>>>>>>>>>> Sorry, I was not able to send much time on this.
>>>>>>>>>>> I would prefer you
>>>>>>>>>>> move the code to
>>>>>>>>>>>
>>>>>>>>>>> xlators/mgmt/glusterd/plugins/src/zfs-specifs-stuffs
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> How about having it under
>>>>>>>>>>> xlators/mgmt/glusterd/plugins/snapshot/src/zfs-specifs-stuffs
>>>>>>>>>>> such that
>>>>>>>>>>> in future if we have to write plugins for other
>>>>>>>>>>> features they can be
>>>>>>>>>>> segregated?
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> It would be nicer to avoid "specific-stuff" or
>>>>>>>>>>> similar from the naming. We can probably leave it at
>>>>>>>>>>> xlators/mgmt/glusterd/plugins/snapshot/src/zfs. The
>>>>>>>>>>> naming would be sufficient to indicate that code is
>>>>>>>>>>> specific to zfs snapshots.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I don't think the directory would be named
>>>>>>>>>>> "zfs-specific_stuffs, instead zfs specific source file
>>>>>>>>>>> will come directly under
>>>>>>>>>>> "xlators/mgmt/glusterd/plugins/snapshot/src/". I think I
>>>>>>>>>>> should have been more clear, my bad.
>>>>>>>>>>> -Rajesh
>>>>>>>>>>> _________________________________________________
>>>>>>>>>>> Gluster-devel mailing list
>>>>>>>>>>> Gluster-devel at gluster.org <mailto:Gluster-devel at gluster.org>
>>>>>>>>>>> http://www.gluster.org/mailman/listinfo/gluster-devel
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>
>>
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