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From:shawn Date:May 13 2017 7:54pm
Subject:Re: Ssd vs mix of ssd and spinning disk
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Hi Shain,

On 5/8/2017 1:53 PM, Shain Miley wrote:
> Hello,
> We have traditionally setup our mysql database servers with a mix of ssd and spinning
> disk drives.
> We use the ssd drives (Raid-1) for the mysql tablespace data, and we use the spinning
> disks (15 sas in Raid-1) for the index data, etc.
> I am wondering if going forward we should simply put all of the data on the ssd
> drives. Does anyone have any information on whether or not we would see any significant
> performance increase if we made this switch?
> I have been thinking about using 4 ssd drives (Raid-10) going forward…and
> wondering if we should expect to see any improvement in the database performance.
> Any thoughts?
> Thanks in advance,
> Shain

If you would benefit from shifting storage technologies depends on how 
limiting your current devices are to your overall throughput.

In most cases, workloads are either CPU-bound (normally due to poor 
choices in table design or query patterns) or DISK-bound (too many reads 
and writes, i/o requests,  for the device to keep up).

Occasionally systems become MEMORY-bound (normally due to poor 
configuration choices which push the system to using swap) or 
NETWORK-bound (the number of concurrent network round trips to complete 
a task is higher than the components can handle).

Of those 4 situations, which is contributing most to your total response 

For example, are you spending more time waiting for data to be buffered 
in from disk than you are computing and returning the results? If so, 
faster disks could help temporarily.

What may help more (and for a longer time) is to improve your storage 
and retrieval patterns (table and query designs) to require less 
frequent trips to disk (aka, better buffering) or to need smaller slices 
of each table (more selective indexes, querying for fewer columns, 
sharding tables, sharding data to different instances, partitioning 
data, ... ).

Shawn Green
MySQL Senior Principal Technical Support Engineer
Oracle USA, Inc. - Integrated Cloud Applications & Platform Services
Office: Blountville, TN

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Ssd vs mix of ssd and spinning diskShain Miley8 May
  • Re: Ssd vs mix of ssd and spinning diskReindl Harald8 May
  • Re: Ssd vs mix of ssd and spinning diskshawn l.green13 May