Goffredo Baroncelli wrote: > > Instead I would like to investigate the idea of COW-ing the stripe: instead of updating the stripe on place, why not write the new stripe in another place and then update the data extent to point to the new data ? Of course would work only for the data and not for the metadata. We are saying the same. What I am suggesting is to write it as RAID1 instead of RAID5, so that if it's changed a lot of times, you pay only once. The background process would then turn it back to RAID5 at a later point. Adjusting how aggressively this background process works enables to adjust the extra write cost versus saved disk space compromise.
