[linux-lvm] Performance penalty for 4k requests on thin provisioned volume

Zdenek Kabelac zkabelac at redhat.com
Thu Sep 14 11:13:41 UTC 2017


Dne 14.9.2017 v 12:57 Gionatan Danti napsal(a):
> On 14/09/2017 11:37, Zdenek Kabelac wrote:
>> Sorry my typo here - is NOT ;)
>>
>>
>> Zdenek
> 
> Hi Zdenek,
> as the only variable is the LVM volume type (fat/thick vs thin), why the thin 
> volume is slower than the thick one?
> 
> I mean: all other things being equal, what is holding back the thin volume?



So few more question:

What is '/dev/sdb4'  ? - is it also some fast SSD ?

([thinpool_tmeta] volgr0 ewi-ao----  16.00g  1     0  /dev/sdb4:0-4095
  - just checking to be sure your metadata device is not placed on rotational 
storage device)...

What is your thin-pool chunk size - is it 64K ?
- if your raise thin-pool chunk size up - is it getting any better ?


Regards

Zdenek




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