[CentOS] cyrus spool on btrfs?

[John R Pierce]

On 9/9/2017 9:47 AM, hw wrote:
>
> Isn´t it easier for SSDs to write small chunks of data at a time?
> The small chunk might fit into some free space more easily than
> a large one which needs to be spread out all over the place. 


the SSD collects data blocks being written and when a full flash block 
worth of data is collected, often 256K to several MB, it writes them all 
at once to a single contiguous block on the flash array, no matter what 
the 'address' of the blocks being written is.  think of it as a 
'scatter-gather' operation.

different drive brands and models use different strategies for this, and 
all this is completely opaque to the host OS so you really can't 
outguess or manage this process at the OS or disk controller level.


-- 
john r pierce, recycling bits in santa cruz