Hello Martin! Am Do., 25. März 2021 um 14:06 Uhr schrieb Martin Kennedy <hurricos@xxxxxxxxx>: > > I don't think the garbage collection performed by bcache actually > sends TRIMs to the SSD unless you turn on discard. Without sending > TRIMs you cannot expect a cheap SSD (or pair of cheap ones in RAID1) > to keep up performance. > > After some small load over the month past, I've done another test to > verify that performance has not degraded: If you want to make use of trimmed space without using online discard, your best chance is to create a blank partition on the caching device after the bcache partition, blkdiscard that, and never touch it. Now re-create bcache in the first partition. The blank partition should be around 10-20% of your device size. This way, the SSD firmware can still do background wear-leveling by swapping flash pages with the untouched partition and do background gc/erase. This will keep bcache latency low, and performance should be stable.
