On August 3, 2015 3:11:53 PM EDT, Chris Murphy <lists@colorremedies.com> wrote:
On Mon, Aug 3, 2015 at 12:51 PM, Andrei Borzenkov <arvidjaar@gmail.com> wrote:
В Mon, 3 Aug 2015 12:33:56 -0600 Chris Murphy <lists@colorremedies.com> пишет:
Actually it is exactly what CoW is. It is btrfs which is not CoW -
more
appropriate name is "redirect on write" or "write anywhere" (which is how oldest implementation is called).
There is no "copy" involved in btrfs write process.
COW semantically means deduplication,
"When I use a word," Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean—neither more nor less."
Please, please - CoW snapshot means - before new data is WRITTEN, original data is COPIED somewhere else.
No, that's just how LVM thick did it. LVM thin does it differently, and it's COW.
CoW snapshots have absolutely nothing to do with deduplication and existed long before deduplication started to be used in storage world.
You're just thinking of this in terms of the LVM thick implementation, not the long standing denotation of the term. It was something of an evil necessity that LVM did it the way it did it, and that's why it doesn't perform well and will eventually be supplanted by LVM thin snapshots.
Got a link describing LVM thin snapshots? I thought they were just traditional snapshots applied to thin provisioned volumes. Greg -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org