On 2017/8/9 下午3:09, cgxu wrote: > HI > > I make bcache device using NVMe ssd device as cache and 4T SATA disk as backing device. > > I found write performance is extremely poor in writeback cache_mode but raw ssd has very high performance. > > I monitored io workload using iostat for a while, so I'm sure it really worked in writeback mode. > > can anyone explain this problem？ Is there any compatible issue with special hardware? Could you please to provide exact steps to reproduce the poor performance situation ? When back ground writeback and garbage collection is performing, front end regular I/O (especially write I/O) performance is expected to downgrade. -- Coly Li -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
