Subject: Re: Why HDD performance is better than SSD in this case
To: Robert Zenz <robert.zenz@sibvisions.com>,
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From: Nicolas Charles <nicolas.charles@normation.com>
Message-ID: <24d62ee0-edd6-fd53-3a3d-8ab1dacd9c35@normation.com>
Date: Tue, 17 Jul 2018 16:08:28 +0200
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Le 17/07/2018 à 15:50, Robert Zenz a écrit :
> On 17.07.2018 15:44, Nicolas Charles wrote:
>> - Partitions is not correctly aligned on the SSD blocks
> Does that really make a noticeable difference? If yes, have you got some further
> reading material on that?

I was pretty sure it was, but looking at the litterature, it's not that 
obvious. Especially 
https://blog.pgaddict.com/posts/postgresql-performance-on-ext4-and-xfs 
seems to mentions that it doesn't change a thing, while others stress 
out that it is mandatory ( https://www.alibabacloud.com/forum/read-415, 
https://www.thomas-krenn.com/en/wiki/Partition_Alignment )
Even on mecanical drives it's been reported to cause slowdown ( 
https://www.ibm.com/developerworks/library/l-linux-on-4kb-sector-disks/index.html 
)

Maybe the OS are more clever now, making it not so important as before ?

Nicolas