search

westerndigitalcorporation / zenfs

ZenFS is a storage backend for RocksDB that enables support for ZNS SSDs and SMR HDDs.
GNU General Public License v2.0
235 stars 86 forks source link

Will Zone::Finish cause device io? #252

Closed attack204 closed 1 year ago

attack204 commented 1 year ago

I want to count the write amplification of ZenFS, so I need to calculate device io. One thing is not for sure that Zone::Finish will move the write pointer to the end, will this operation in the ZNS SSD layer cause write io? I mean it directly moves wp to the end or fills some invalid data? And the same problem in Zone::Reset, will this cause device io before it moves wp to start?

yhr commented 1 year ago

It depends on controller implementation. Finishes may cause write amp on the drive, but necessarily so, same thing with resets on non-full zones.

attack204 commented 1 year ago

That's really helpful. So I think I should count 2 write amplifications. One is count Finish/Reset io and the other is not.