ср, 23 окт. 2019 г. в 11:20, Coly Li <colyli@xxxxxxx>: > > On 2019/10/23 3:12 上午, Eric Wheeler wrote: > > On Tue, 15 Oct 2019, Coly Li wrote: > >> I have no much idea. The 4Kn SSD is totally new to me. Last time I saw > >> Eric Wheeler reported 4Kn hard diver didn't work well as backing device, > >> and I don't find an exact reason up to now. I am not able to say 4Kn is > >> not supported or not, before I have such device to test... Coly, thank you for your reply. It seems I'll have ot do some more tests and dive a little into bcache sources when I have time. Meanwhile, could you please explain what cache_bypass_misses and cache_bypass_hits mean? It's not obvious from the docs. > Yes, this is the problem I wanted to say. Kent suggested me to look into > the extent code, but I didn't find anything suspicious. Also I tried to > buy a 4Kn SSD, but it seemed not for consumer market and I could not > find it from Taobao (www.taobao.com). I'm using SANDISK Extreme Pro SDSSDXPM2-500G-G25 M.2 NVMe drive and it's quite common desktop drive, just use native 4K format (nvme-cli) LBA Format 0 : Metadata Size: 0 bytes - Data Size: 512 bytes - Relative Performance: 0x2 Good LBA Format 1 : Metadata Size: 0 bytes - Data Size: 4096 bytes - Relative Performance: 0x1 Better (in use) I'm not sure, but I think other drives support this too. ---- Best regards, Sergey.
