DragonFly kernel List (threaded) for 2007-02
Re: Plans for 1.8+ (2.0?)
Tobias Schacht wrote:
On 2/1/07, Matthew Dillon <email@example.com> wrote:
No, its a lot more complex then that. There are three basic issues:
* Redundancy in a heavily distributed environment
* Transactional Consistency.
* Cache Coherency and conflict management.
Hm, I wonder how plan9 solved these issues? AFAIK they have at least a
snapshots capable fs (long before zfs) and since their scope also is a
distributed environment, it may be a good idea to take a look and
maybe borrow some ideas?
But I'm really no expert here, so anybody with a clue is invited to
comment on that. ;)
The Plan 9 storage (two distinct types) was 'widely sharable', not clustered,
One might make the case that it had more in common with NFS than clustering.
BUT.. it had a mechanism to insure 'current status' more familiar to table, row,
record locking schemes of an RDBMS (which ZFS has a kinship with).
Simple hash-based, these were an order or two of magnitude simpler - hence
faster - than ZFS could be on the same hardware.
The consatnt 'snapshot-ing' OTOH, could have placed major strains on the paltry
storage of the day (for anyone with less funding than AT&T anyway).
That last part has changed.
With capacity and cost of current HDD, it is probably now faster and cheaper to
'abandon in place' a good deal of stale data than to even bother to go back and
look at it at all - let alone clean it up, make decisions as to what to archive,
Not complex, and certainy worth a look for recyclable ideas. her is an analysis
of 'in-use' history: