3 ms·
Sometimes. Other times they may make things worse by lying to the filesystem (and thereby also the application) about writes being completed, which may confound
by amarshall 5y ago
Sometimes. Other times they may make things worse by lying to the filesystem (and thereby also the application) about writes being completed, which may confound higher-level consistency models.
- wtallis 5y agoIt does seem to me that it's much easier to reason about the overall system's resiliency when the capacitor-protected caches are in the drives themselves (standard for server SSDs) and nothing between that and the OS lies about data consistency. And for solid state storage, you probably don't need those extra layers of caching to get good performance.
- karmakaze 5y agoSince my experience was from a number of years back, I tried searching for more recent reports: "mysql ssd fsync performance". The top recent one I found was for Digital Ocean[0] in 2020. It says "average of about 20ms which matches your 50/sec" and mentions battery back-up controllers which wasn't even in my search terms. [0] https://www.digitalocean.com/community/questions/poor-fsync-performance-on-do-block-storage https://www.digitalocean.com/community/questions/poor-fsync-...