I asked this because I have big needs in fast MySQL replication under Debian 8/9 systems, and we had got problems with these systems when they have Micron SSD hard disks. I don’t know why, but some hard disk models seem to be very slower (10x slower) than others under standard debian 8/9 + mysql 5.7. We always run 2 disks in hardware RAID0 to get enough performances for our needs.
- Servers with Micron 1100 MTFDDAK512BTN M0MU031 500GB SSD : too much slow for us : MySQL replication becomes late, so we can’t use in production. Tested 3 times, 3 slow servers.
- Servers with Samsung 850 EVO EMT02B6Q 500GB SSD : works well, 10x faster, validated for our production use. We run 6 of them.
- 1 server with Samsung MZ7LN512HCHP-00000 EMT0100Q work well too.
All these server are installed the same way, I am 100% sure of this : the hard disk model is the problem.
The problem for me is that all most recent Online servers we took were hosted with the Micro hard drive. We could not do anything else than stop them or use them for something else than our fast-mysql-replication needs : we could not use them. Too slow.
So today I can’t buy new servers from Online until I am sure that the server I will get will host a hard disk that WE validated for production. That’s a real problem for me because I loved to work with you, and I need to keep a balanced division between three hosting providers, for high-availability policy reason.
This problem with some hard disks model is very strange sometimes : we got the same with another host, with two very near and similar hard disks references. Under Debian 8 + MySQL 5.7 standard systems :
- Intel 480GB SSD all work fine, event using soft RAID0 (where we need hard RAID0 everywhere else, because of our speed needs). We today use these models fine :
- But 1 model : Intel SSDSC2BB480H4, was 10x slower than the others, for exactly the same use. Tested 2 times.
Crazy, isn’t it ?