[Gluster-users] Gluster tier in progress after attach

[Jeevan Patnaik]

Hi,

Yes, I did. The status shows all as completed.

Regards,
Jeevan.

On Mon 24 Sep, 2018, 9:20 PM Nithya Balachandran, <nbalacha at redhat.com>
wrote:

>
>
> On 24 September 2018 at 21:01, Jeevan Patnaik <g1patnaik at gmail.com> wrote:
>
>> Hi,
>>
>> What do you mean by expanding volume?
>>
>> I mean adding new bricks to extend storage. It is mentioned that
>> detaching tier is must for adding or removing bricks.
>>
>> What command did you use to detach the tier? And how did you check that
>> the files still exist on the hot tier?
>>
>> gluster volume tier volume_name detach start
>>
>> I check the files directly from backend filesystem on disk and there are
>> still left over files on all hot tier disks.
>>
>> Anyhow I proceeded with detach commit to see what would happen..so after
>> commit, I can't access those files from client filesystems..so they're gone
>> with the hot tier and were not moved to cold tier.
>>
>
> Did you check that the detach tier operation had completed before running
> detach commit?
>
>>
>> And even if I try to attach the hot tier bricks again to bring back the
>> files, attach won't work with existing files.
>>
>> So, it seems we shouldn't detach hot tier without making sure all files
>> are moved to cold tier..but in my case, some files just won't move, even
>> though they aren't being accessed anywhere.
>>
>
>
>
>>
>> There's a statement saying POSIX locks can cause files to be still left
>> in hot tier and in that case, either the application causing posix lock has
>> to be closed or files should be moved manually (but where?)... however, I
>> don't think in my case there's any posix locks as the files are not
>> accessed by any application except gluster itself.
>>
>> Regards,
>> Jeevan.
>>
>>
>> On Mon 24 Sep, 2018, 8:45 PM Nithya Balachandran, <nbalacha at redhat.com>
>> wrote:
>>
>>> It has been a while since I worked on tier but here is what I remember:
>>>
>>>
>>> On 24 September 2018 at 19:15, Jeevan Patnaik <g1patnaik at gmail.com>
>>> wrote:
>>>
>>>> Hi Nithya,
>>>>
>>>> No..the files are not being accessed. And tiering mode is in cache mode
>>>> and what I understood is in cache mode every file is moved to hot tier
>>>> until it reaches low watermark, then it only promotes highly accessed files.
>>>>
>>>> Not quite . All files will initially exist on the cold tier. Any new
>>> files will be created on the hot tier. Any old files that are accessed will
>>> be promoted ot the hot tier.
>>>
>>>
>>> And do you mean everytime we expand volume,  we are virtually flushing
>>>> the tier and it regenerates only when a files are accessed?
>>>>
>>>> What do you mean by expanding the volume?
>>>
>>>
>>>> Also I see one more issue now, I hav generated another 1000 files after
>>>> tiering is started and I see all 1000 files are now created on hot tier.
>>>> Now, I detached again..in detach status it shows completed..but when I
>>>> checked, around 260 files are still located on hot tier..those files are
>>>> not being used anywhere..ca you tell why are they still not moved to cold
>>>> tier and why the detach status is showing a wrong status.
>>>>
>>>
>>> What command did you use to detach the tier? And how did you check that
>>> the files still exist on the hot tier?
>>>
>>> Regards,
>>> Nithya
>>>
>>>>
>>>> I am using gluster 3.12.3 and server hosts include RHEL 6.7 and 7.2
>>>> hosts also.
>>>>
>>>> Regards,
>>>> Jeevan.
>>>>
>>>> On Mon 24 Sep, 2018, 7:00 PM Nithya Balachandran, <nbalacha at redhat.com>
>>>> wrote:
>>>>
>>>>> Are those files being accessed? Tiering will only promote those that
>>>>> have been accessed recently.
>>>>>
>>>>> Regards,
>>>>> Nithya
>>>>>
>>>>> On 24 September 2018 at 18:32, Jeevan Patnaik <g1patnaik at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> I see it still not promoting any files. Do we need to run any command
>>>>>> to force the movement?
>>>>>>
>>>>>> This would be an issue if we need to expand disk as then we also need
>>>>>> to detach existing tier and attach again and expect the data to be promoted
>>>>>> to the hot tier.
>>>>>>
>>>>>> Regards,
>>>>>> Jeevan.
>>>>>>
>>>>>> On Mon 24 Sep, 2018, 6:17 PM Jeevan Patnaik, <g1patnaik at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I have created a 18 disk replica 3 volume and created 1000 random
>>>>>>> files each of 10M.
>>>>>>>
>>>>>>> Later I have attached 15 disk replica 3 tier with each hot tier disk
>>>>>>> coming from cold tier host, except on 3 (as we don't have hot tier disk)
>>>>>>>
>>>>>>> After attach, I see no files are promoted at even after 15 minutes.
>>>>>>> Status is showing as In progress.
>>>>>>>
>>>>>>> Is it always this much slow? For 10G data, 15 minutes is too much
>>>>>>> Also will the data try to be promoted to a hot tier coming from the
>>>>>>> same host to reduce the time taken to move the files?
>>>>>>>
>>>>>>> Cold tier is made of RAID supported SSD and hot tier is made of NVMe
>>>>>>> SSDs.
>>>>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>> Jeevan.
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> Gluster-users mailing list
>>>>>> Gluster-users at gluster.org
>>>>>> https://lists.gluster.org/mailman/listinfo/gluster-users
>>>>>>
>>>>>
>>>>>
>>>
>
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