[Pan-users] Re: Weird cache problem

[Duncan]

Jim Henderson posted on Sat, 29 Aug 2009 03:54:04 +0000 as excerpted:

> Come to think, there is a third oddity that I just realized was new -
> occasionally when hitting groups on forums.opensuse.org, a group's
> headers will completely redownload, and old messages (that haven't
> expired) will show up as unread.

That one's almost always a server oddity -- due to xref: renumbering.  
However, in your case, given the other issues, it sounds like you may 
have more complex problems.

You don't happen to have ECC backed memory, do you?  If for some reason 
your memory (or for that matter, your disk, or maybe the bus connecting 
the disk to the machine) is going bad, you may be getting bit-flips that 
are turning one thing into something entirely different.  ECC backed 
memory is designed to try to detect and correct such issues with memory, 
and there are disk based solutions as well, but neither one is 
particularly common yet, and ecc memory is much more expensive as it 
requires additional chips on the memory modules (and because they /are/ 
more expensive, they're not as common, which makes them even /more/ 
expensive, ecc memory is thus normally considered a server option and 
rarely available in desktops/laptops).

I'd try something like memtest.  Just because it says you're clean 
doesn't necessarily mean you are (it doesn't stress the memory bus, just 
the cells, so if it's memory that's barely within tolerance at the rated 
clockspeed, it may not show up, I had that problem with some memory at 
one point), but if it says your memory is dodgy, better replace it before 
you start having worse issues.

And check the cable seating to your drives, etc, as well.

Whatever's happening, it does seem strange, that's for sure!  FWIW, one 
of the best indicators I had a problem with my memory (the memory 
clocking issue mentioned above, it went away when I declocked the memory 
a notch) was that bzip2 would often complain trying to decompress 
something, as it's well checksummed.  Big compiles would often error out 
as well, but big compiles aren't so common on binary distributions.  But 
try bzip2-ing a bunch of files, then bunzip2ing them, and see if bunzip2 
complains about any of them.  If it does, you're a sure candidate for 
physical system issues, memory, disk, otherwise, but somewhere!

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman