On 2014/05/16 11:36 PM, Austin S Hemmelgarn wrote:
On 05/16/2014 04:41 PM, Tomasz Chmielewski wrote:
On Fri, 16 May 2014 14:06:24 -0400
Calvin Walton <calvin.wal...@kepstin.ca> wrote:
No comment on the performance issue, other than to say that I've seen
similar on RAID-10 before, I think.
Also, what happens when the system crashes, and one drive has
several hundred megabytes data more than the other one?
This shouldn't be an issue as long as you occasionally run a scrub or
balance. The scrub should find it and fix the missing data, and a
balance would just rewrite it as proper RAID-1 as a matter of course.
It's similar (writes to just one drive, while the other is idle) when
removing (many) snapshots.
Not sure if that's optimal behaviour.
[snip]
Ideally, BTRFS should dispatch the first write for a block in a
round-robin fashion among available devices. This won't fix the
underlying issue, but it will make it less of an issue for BTRFS.
More ideally, btrfs should dispatch them in parallel. This will likely
be looked into for N-way mirroring. Having 3 or more copies and working
in the current way would be far from optimal.
--
__________
Brendan Hide
http://swiftspirit.co.za/
http://www.webafrica.co.za/?AFF1E97
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
