[issue1556] many processes stuck in "hmrrcm", system unusable

[Bill Hacker]

Alex Hornung (via DragonFly issue tracker) wrote:
Alex Hornung <ahornung at gmail.com> added the comment:

: Corecode's report is the only one we have, and we don't have a realistic
: test scenario that measures when it happens or how much it happens. 
This is not really true. Hasso has also been complaining about very bad 
performance and even showed some test cases and results running dd in various 
scenarios. I also notice quite a performance degradation, especially working 
with git. git diff and checkout particularly take ages on hammer.

: Before we have Matt, who can work full-time on clustering - the _purpose
: of this project_ - digress for months on filesystem performance, can we
: quantify the actual problem?
To quantify the problem should be straight forward. As I mentioned before, 
hasso did some of it, but in any case there are test programs (thinking dbench 
or similar here, don't know if anyone of them is in pkgsrc) who can quantify it 
easily.
About clustering being the main goal... the original goal, as far as I know, 
was to have a well performing SMP system. Right now our SMP performance isn't 
exactly good. I know that the main page is now full of references to clustering 
being *THE* goal, but what happened to the original goals?

Cheers,
Alex Hornung
Not to put too fine a point on it, but ISTR that HAMMER was originally a 
serendipitous target of opportunity *en route* to SMP and clustering.

That said, if HAMMER *does* need work, well.... surely the goal is not to 
cluster a problematic fs.

The woods are full of those already.

Bill Hacker