[Gluster-users] gluster over vdo, problem with gfapi

[Strahil Nikolov]

I am not sure that it  is ok to use any caching (at least ovirt  doesn't uses) .

Have you set the 'virt' group of  settings ? They seem to be optimal , but keep in mind that  if you enable them -> you will enable sharding  which cannot be 'disabled' afterwards.

The fact that it works on C7 is strange,  with wifh version of gluster did you test.

Best Regards,
Strahil Nikolov

На 12 август 2020 г. 18:03:29 GMT+03:00, Dmitry Melekhov <dm at belkam.com> написа:
>
>12.08.2020 17:50, Strahil Nikolov пишет:
>> 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
>>
>> На 12 август 2020 г. 16:34:26 GMT+03:00, Satheesaran Sundaramoorthi
><sasundar at redhat.com> написа:
>>> On Wed, Aug 12, 2020 at 2:30 PM Dmitry Melekhov <dm at belkam.com>
>wrote:
>>>
>>>> 12.08.2020 12:55, Amar Tumballi пишет:
>>>>> 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