Re: ceph df: Raw used vs. used vs. actual bytes in cephfs

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Could you be running into block size (minimum allocation unit)
overhead? Default bluestore block size is 4k for hdd and 64k for ssd.
This is exacerbated if you have tons of small files. I tend to see
this when "ceph df detail" sum of raw used in pools is less than the
global raw bytes used.

On Mon, Feb 19, 2018 at 2:09 AM, Flemming Frandsen
<flemming.frandsen@xxxxxxxxxxxxxxxx> wrote:
> Each OSD lives on a separate HDD in bluestore with the journals on 2GB
> partitions on a shared SSD.
>
>
> On 16/02/18 21:08, Gregory Farnum wrote:
>
> What does the cluster deployment look like? Usually this happens when you’re
> sharing disks with the OS, or have co-located file journals or something.
> On Fri, Feb 16, 2018 at 4:02 AM Flemming Frandsen
> <flemming.frandsen@xxxxxxxxxxxxxxxx> wrote:
>>
>> I'm trying out cephfs and I'm in the process of copying over some
>> real-world data to see what happens.
>>
>> I have created a number of cephfs file systems, the only one I've
>> started working on is the one called jenkins specifically the one named
>> jenkins which lives in fs_jenkins_data and fs_jenkins_metadata.
>>
>> According to ceph df I have about 1387 GB of data in all of the pools,
>> while the raw used space is 5918 GB, which gives a ratio of about 4.3, I
>> would have expected a ratio around 2 as the pool size has been set to 2.
>>
>>
>> Can anyone explain where half my space has been squandered?
>>
>>  > ceph df
>> GLOBAL:
>>      SIZE      AVAIL     RAW USED     %RAW USED
>>      8382G     2463G        5918G         70.61
>> POOLS:
>>      NAME                         ID     USED       %USED     MAX
>> AVAIL     OBJECTS
>>      .rgw.root                    1        1113         0 258G
>> 4
>>      default.rgw.control          2           0         0 258G
>> 8
>>      default.rgw.meta             3           0         0 258G
>> 0
>>      default.rgw.log              4           0         0 258G
>> 207
>>      fs_docker-nexus_data         5      66120M     11.09 258G
>> 22655
>>      fs_docker-nexus_metadata     6      39463k         0 258G
>> 2376
>>      fs_meta_data                 7         330         0 258G
>> 4
>>      fs_meta_metadata             8        567k         0 258G
>> 22
>>      fs_jenkins_data              9       1321G     71.84 258G
>> 28576278
>>      fs_jenkins_metadata          10     52178k         0 258G
>> 2285493
>>      fs_nexus_data                11          0         0 258G
>> 0
>>      fs_nexus_metadata            12       4181         0 258G
>> 21
>>
>> --
>>   Regards Flemming Frandsen - Stibo Systems - DK - STEP Release Manager
>>   Please use release@xxxxxxxxx for all Release Management requests
>>
>> _______________________________________________
>> ceph-users mailing list
>> ceph-users@xxxxxxxxxxxxxx
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
>
> --
>  Regards Flemming Frandsen - Stibo Systems - DK - STEP Release Manager
>  Please use release@xxxxxxxxx for all Release Management requests
>
>
> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
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