Gluster users - Aug 2020 - gluster over vdo, problem with gfapi

Libgfapi brings far better performance , but qemu has some limitations.


If it works on FUSE , but not on libgfapi -> it seems obvious.

Have you tried to connect from C7 to the Gluster TSP via libgfapi.

Also,  is SELINUX in enforcing or not ?

Best Regards,
Strahil Nikolov

?? 12 ?????? 2020 ?. 16:34:26 GMT+03:00, Satheesaran Sundaramoorthi <sasundar
at redhat.com> ??????:
>On Wed, Aug 12, 2020 at 2:30 PM Dmitry Melekhov <dm at belkam.com>
wrote:
>
>> 12.08.2020 12:55, Amar Tumballi ?????:
>> > Hi Dimitry,
>> >
>> > Was this working earlier and now failing on Version 8 or is this a
>new
>> > setup which you did first time?
>> >
>> Hello!
>>
>>
>> This is first time we  are testing gluster over vdo.
>>
>> Thank you!
>>
>>
>> Hello Dmitry,
>
>I have been testing the RHEL downstream variant of gluster with RHEL
>8.2,
>where VMs are created with their images on fuse mounted gluster volume
>with
>VDO.
>This worked good.
>
>But I see you are using 'gfapi', so that could be different.
>Though I don't have valuable inputs to help you, do you see
'gfapi'
>good
>enough than using fuse mounted volume
>
>-- Satheesaran S

12.08.2020 17:50, Strahil Nikolov ?????:
> Libgfapi brings far better performance ,
Yes, and several vms do not rely on the same mount point...

> but qemu has some limitations.
>
>
> If it works on FUSE , but not on libgfapi -> it seems obvious.

Not obvious for me, we tested vdo locally, i.e. without gluster and qemu 
works with cache=none or cache=directsync without problems,

so problem is somewhere in gluster.
>
> Have you tried to connect from C7 to the Gluster TSP via libgfapi.
No, but we tested the same setup with gluster 7 with the same result 
before we upgraded to 8.
>
> Also,  is SELINUX in enforcing or not ?
selinux is disabled...


Thank you!
>
> Best Regards,
> Strahil Nikolov
>
> ?? 12 ?????? 2020 ?. 16:34:26 GMT+03:00, Satheesaran Sundaramoorthi
<sasundar at redhat.com> ??????:
>> On Wed, Aug 12, 2020 at 2:30 PM Dmitry Melekhov <dm at
belkam.com> wrote:
>>
>>> 12.08.2020 12:55, Amar Tumballi ?????:
>>>> Hi Dimitry,
>>>>
>>>> Was this working earlier and now failing on Version 8 or is
this a
>> new
>>>> setup which you did first time?
>>>>
>>> Hello!
>>>
>>>
>>> This is first time we  are testing gluster over vdo.
>>>
>>> Thank you!
>>>
>>>
>>> Hello Dmitry,
>> I have been testing the RHEL downstream variant of gluster with RHEL
>> 8.2,
>> where VMs are created with their images on fuse mounted gluster volume
>> with
>> VDO.
>> This worked good.
>>
>> But I see you are using 'gfapi', so that could be different.
>> Though I don't have valuable inputs to help you, do you see
'gfapi'
>> good
>> enough than using fuse mounted volume

We think that gfapi is better for 2 reasons:

1. it is faster;

2. each qemu process connects to gluster cluster , so there is no one 
point of failure- fuse mount...


Thank you!
>>
>> -- Satheesaran S