Optimizing Database to reduce writes to SSD

Optimizing Database to reduce writes to SSD
There are a lot of things you can do on the database size as well:

Mix HDD and SSD – HDD when paired with RAID with BBU (Write Cache) can perform writes very well if they go to the small area on disk or sequential. You can use it to put some of the data to hard drives instead of SSD to reduce amount of writes to SSD.
Store DoubleWrite Buffer on HDD – Double Write Buffer is a killer for SSDs essentially doubling amount of writes for data changed in your tablespaces. At the same time this is a very small area (few MB in size) which is constantly updated as such it can very well be on the HDD as long as you have the BBU Cache. In Percona Server you can keep Double Write Buffer in the Separate File while in any MySQL version you can simply put your system tablespace on HDD. For most workloads it will be small enough to be cached.
Store Transactional Logs on HDD – Innodb Transactional Logs is another candidate for HDD – they are written sequentially so HDDs+ RAID BBU cache may well keep up very well with your load.
Store Binary Logs on HDD – Binary Logs… another object which is read and written sequentially as such it does not need to be on SSD.
Temporary Space in Memory – Temporary space (tmpdir) can get a lot of writes and you do not want them to be hitting your SSD. The best is to use tmpfs file system which allocates it in memory (or swap file if there is not enough memory) unless you have extremely large temporary space needs.
Large Buffer Pool Size – The larger your bufferpool hopefully more dirty pages you can keep and as such more writes will come to already dirty pages effectively eliminating IO to SSD. So even if SSDs means you often can do with smaller memory amounts to achieve performance you need you might still want memory to increase your SSD life time.
Large Innodb Log Files – The larger are your Innodb Log files the more you can delay writes and as such the more logical writes can be merged into the single physical write. SSDs are fast so you often can get crash recovery speed you need with a lot larger log files than you had on HDDs. The combined log files size of 10GB may well work for your application.
Innodb Compression – Innodb Compression reduces amount of data written to tablespace hence can increase life time. Note in some MySQL versions compression increases amount of space written to Innodb Log Files, in this case it is good combined with Innodb Log Files being on Hard drive.
Alternative Storage Engines – TokuDB seems to be offering higher compression ratio and more sequential writes so it might be better choice for your application from SSD life standpoint. It would be interesting to see some real life comparisons in how much writes both engine generate for same workload.


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