On 04/28/2014 08:47 AM, Karl Denninger wrote:
The odd thing is that I am getting better performance with a 128k record
size on this application than I get with an 8k one! Not only is the
system faster to respond subjectively and can it sustain a higher TPS
load objectively but the I/O busy
Karl Denninger wrote:
I've been doing a bit of benchmarking and real-world performance
testing, and have found some curious results.
[...]
The odd thing is that I am getting better performance with a 128k record
size on this application than I get with an 8k one!
[...]
What I am curious
On 4/29/2014 3:13 AM, Albe Laurenz wrote:
Karl Denninger wrote:
I've been doing a bit of benchmarking and real-world performance
testing, and have found some curious results.
[...]
The odd thing is that I am getting better performance with a 128k record
size on this application than I get
On 4/28/2014 1:04 PM, Heikki Linnakangas wrote:
On 04/28/2014 06:47 PM, Karl Denninger wrote:
What I am curious about, however, is the xlog -- that appears to suffer
pretty badly from 128k record size, although it compresses even
more-materially; 1.94x (!)
The files in the xlog directory are
On 04/28/2014 06:47 PM, Karl Denninger wrote:
What I am curious about, however, is the xlog -- that appears to suffer
pretty badly from 128k record size, although it compresses even
more-materially; 1.94x (!)
The files in the xlog directory are large (16MB each) and thus first
blush would be
On 04/28/2014 09:07 PM, Karl Denninger wrote:
The WAL is fsync'd frequently. My guess is that that causes a lot of
extra work to repeatedly recompress the same data, or something like
that.
It shouldn't as ZFS re-writes on change, and what's showing up is not
high I/O*count* but rather
On Mon, Apr 28, 2014 at 11:07 AM, Karl Denninger k...@denninger.net wrote:
On 4/28/2014 1:04 PM, Heikki Linnakangas wrote:
On 04/28/2014 06:47 PM, Karl Denninger wrote:
What I am curious about, however, is the xlog -- that appears to suffer
pretty badly from 128k record size, although it
On 4/28/2014 1:22 PM, Heikki Linnakangas wrote:
On 04/28/2014 09:07 PM, Karl Denninger wrote:
The WAL is fsync'd frequently. My guess is that that causes a lot of
extra work to repeatedly recompress the same data, or something like
that.
It shouldn't as ZFS re-writes on change, and what's
On 4/28/2014 1:26 PM, Jeff Janes wrote:
On Mon, Apr 28, 2014 at 11:07 AM, Karl Denninger k...@denninger.net
mailto:k...@denninger.net wrote:
Isn't WAL essentially sequential writes during normal operation?
Only if you have some sort of non-volatile intermediary, or are
willing to
