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

[Zdenek Kabelac]

Dne 14.9.2017 v 11:00 Zdenek Kabelac napsal(a):
> Dne 14.9.2017 v 00:39 Dale Stephenson napsal(a):
>>
>>> On Sep 13, 2017, at 4:19 PM, Zdenek Kabelac <zkabelac at redhat.com> wrote:
>>>
>>
>> md127 is an 8-drive RAID 0
>>
>> As you can see, there’s no lvm striping; I rely on the software RAID 
>> underneath for that.  Both thick and thin lvols are on the same PV.
>>>
>>> SSD typically do needs ideally write 512K chunks.
>>
>> I could create the md to use 512k chunks for RAID 0, but I wouldn’t expect 
>> that to have any impact on a single threaded test using 4k request size.  Is 
>> there a hidden relationship that I’m unaware of?
> 
> 
> Yep - it seems the setup in this case is the best fit.

Sorry my typo here - is NOT ;)


Zdenek