[i]Even then, I'm still confused as to how I would do anything much useful with this over and above, say, 1 minute snapshots.[/i]
Hi Nathan, I was hoping to be clear with my examples. Within that 1 minute the user has easily received the mail alert that 5 mails have arrived, has seen the sender and deleted them. Without any trigger of some snapshot, or storage of that state while the messages were actually on the drive. No recovery possible. One minute is much too long. Taking the average reaction time of users, we cannot expect, on the other hand, that the user is able to perform more than two operations within less than a second (receiving the notice, recognising the sender, clicking 'Delete'). On the other hand, one minute is much too frequently w.r.t. efficient usage of resources. The normal situation on a workstation within 1 minute difference in time is, that the file(s) on which the user works, are unmodified. It might please the vendors of hardware and storage space to try a snapshot once per minute, but normally, the actual change content will be zero. Logical consequence: If one minute is much too long w.r.t. recovery and at the same time too short for scheduled snapshots, the whole thing is based on wrong premises. In this case, the wrong assumption that scheduled snapshots could serve the intended purpose of a versioning system comprising all relevant versions. As much as ZFS is revolutionary, it is far away from being the 'ultimate file system', if it doesn't know how to handle event-driven snapshots (I don't like the word), backups, versioning. As long as a high-level system utility needs to be invoked by a scheduler for these features (CDP), and - this is relevant - *ZFS does not support these functionalities essentially different from FAT or UFS*, the days of ZFS are counted. Sooner or later, and I bet it is sooner, someone will design a file system (hardware, software, Cairo) to which the tasks of retiring files, as well as creating versions of modified files, can be passed down, together with the file handlles. No need to believe me. But remember, you read it here first. Uwe This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
