rsync 2.6.0 - suspected memory leak bug

[Alberto Accomazzi]

 > On Wed, Jan 21, 2004 at 03:35:37PM +0000, Kelly Garrett wrote:
 >>>
 >>> Does anyone know how to build a version of the kernel that either 
does no disk
 >>> cacheing (we have very fast RAID processors and SCSI disks on the 
machine) or
 >>> limit the amount of cache that the system will allocate for disk?


Kelly,

we have a similar setup here (RH8 with latest bigmem kernel on a machine 
with 4GB ram and 1.4TB fs) and see a similar behaviour.  Howevever, long 
ago I have accepted this as a "feature" of the linux kernel and I've yet 
to find that this causes any performance issues.  It's true that if your 
file access is truly random caching the filesystem in RAM doesn't help, 
but I can't imagine that this is a significant performance hit.  The 
system simply releases the cache as needed so that even if at any time 
you're seeing 100% memory usage, when a new process needs memory the RAM 
cache will give way.

I'm sure that there are ways to override this behaviour (see for 
instance the linux kernel hacking howto for hints) but I doubt that this 
is worth the effort unless you need to squeeze every last bit of 
performance out of your box.  And if you do, I would suggest looking at 
installing a 2.6.x kernel instead.

-- Alberto


P.S. I found that in our case one thing that actually helped quite a bit 
with overall performance was tuning some kernel parameters for the 
particular raid controller we have (3ware IDE raid).  I mention this 
because if you start going down the performance tuning path there are a 
number of things that you should look at.



**************************************************************************
Alberto Accomazzi, NASA Astrophysics Data System    http://ads.harvard.edu
Harvard-Smithsonian Center for Astrophysics     http://cfa-www.harvard.edu
60 Garden St, MS 31, Cambridge, MA 02138, USA   aaccomazzi at cfa.harvard.edu
**************************************************************************