On 2017-03-07 15:57, Karel Gardas wrote:
RAID10 should be simple. RAID6 is in tree in some form. W.r.t. HAMMER2/ZFS as a ZFS user using ZFS solely for more than 10 years already, I'm not so keen anymore about COW due to fragmentation. Otherwise snapshots are nice, but I'd rather snapshots to be added to ffs in not-so-optimal form and whole fs behaving nicely than having nice snapshots in ZFS and whole fs killed perf-wise by fragmentation.
I'll be interested to see how HAMMER2 handles free space fragmentation. A while back someone on the ZFS team was looking at a way to clean this fragmentation and rewrite the block pointers. The problem ended up being that ZFS has so many features that redoing all of the block pointers would take forever and be very hard to do. Not to mention it also makes adding new features much more difficult.
Something like ZFS with a much more limited feature set would be ideal for this kind of project. But adding FFS snapshots and using softraid would probably be easier and accomplish the same goal.
