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Compared to using a HDD on local computer and do many MySQL read / writes on it, could it have more queries per second if I install 10GBe network cards and I store the MySQL data on a raid network storage made of multiple HDDs ? Or would the network latency (or something else) be a problem for MySQL performance ?

My goal would be to get near SSD read/write performance without wearing out the SSD.

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  • Keep in mind it's a 10 Gigabit network switch, which is the equivalent of 1.25 GB. If you're still using just mechanical HDDs in your raid setup, you won't really be able to come close to a good SSD (but I'm sure it helps).
    – J.D.
    May 16 at 4:38
  • The maximum theoretical 1.25 GB/s is still around double of the 500 GB/s of SATA SSDs, I am considering this too. And around 10 times more than the ~100MB/s single local SATA mechanical HDD.
    – adrianTNT
    May 16 at 12:37
  • Yup, I know. Just normalizing the units of measure for comparison since I/O is measured in -byte units instead of -bit units, and some people sometimes forget that when talking about hardware. NVMes (which I believe are technically considered SSDs) actually can well exceed 1.25 GB/s too. But yea it'll not be likely to emulate SSD speeds with a raid of mechanical disks.
    – J.D.
    May 16 at 13:06
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    Optimize the queries so that the Question becomes moot.
    – Rick James
    May 21 at 2:31

2 Answers 2

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You won’t get close to SSD speeds no matter how you set up HDDs (well, unless you give them a cache). That said, the impact on your application performance is going to be against your IO time only. If you don’t do a lot of IO (because you have so much memory that nothing really hits the disk) then this could be fine. I find that if you build it (a database with fast storage) then they (IO intensive SQL) will come, so you’ve probably already made this a requirement going forwards.

In reality, you may be trying to solve a problem that doesn’t exist - are you really going to wear out your SSDs faster than you can afford? The network attached storage idea with RAID is fine as a general storage solution, but you’re going to want SSDs if your application is already relying on your database being supported by SSD.

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A Hardware RAID controller with Battery Backed Write Cache makes nearly all writes take essentially zero time.

If your app is reporting on Data Warehouse data, the I/O decreases dramatically if you can build and maintain Summary tables.

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  • In another setup, I did notice the nice performance of raid battery cache, but isn't that cache a flash type memory that wears out like an SSD, or even faster ?
    – adrianTNT
    May 22 at 23:32
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    @adrianTNT - Doesn't have to be Flash; it could be old DRAM. If it is Flash, then it probably wears the data evenly by using an appropriate caching algorithm.
    – Rick James
    May 23 at 0:44

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