alt Hacker News> Figure 9: Durable writes with io_uring. Left: Writes and fsync are issued via io_uring or manually linked in the application. Right: Enterprise SSDs do not require fsync after writes.
This sounds strange to me, of not requiring fsync. I may be wrong, but if it was meant that Enterprise SSDs have buffers and power-failure safety modes which works fine without explicit fsync, I think it's too optimistic view here.
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jclulow • last Wednesday at 4:55 AM
Yeah that's just flat out not correct. If you're writing through a file system or the buffer cache and you don't fsync, there is no guarantee your data will still be there after, say, a power loss or a system panic. There's no guarantee it's even been passed to the device at all when an asynchronous write returns.
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I suspect it’s a misunderstanding. PLP capacitors let the drive not flush writes before reporting a write completed in response to a sync request, but they don’t let the software skip making that call.