[conspire] One way to test system RAM

[Rick Moen]

(Note for Darlene, in particular, with thanks for moral and other
support in diagnosing the RAM problem.)

I determined a few days ago that my "new" 2001-era VA Linux Systems
model 2230 2U rackmount server, the intended replacement for the current
linuxmafia.com box, really _did_ have two defective sticks of RAM, out
of four total.

It's just my luck that those were the two big ones:  512 MB each of
3.3v, 168-pin, PC0100 ECC SD-RAM -- 2/3 of the box's total 1.5 GB.

It was a slightly difficult diagnosis, and _two_ sticks of RAM being
simultaneously bad normally is a-priori unlikely, for reasons I detailed
to Darlene, late Saturday night -- but these were sticks I knew were
suspect when I got them second-hand for free, back when my family
honestly had no money at all to spare during the worst of the dot-com
collapse.

Anyhow, I did bite the bullet and buy replacements from S.A.
Technologies, Inc. of Santa Clara (www.satech.com).  They arrived
Wednesday afternoon -- and I faced a pleasantly unfamiliar problem:  How
do you tortunre-test a Linux server with prodigious (by my rather
laughable standards) amounts of RAM?

This is what I came up with:

# cd /usr/src/linux-source-2.6.16
# while : ; do make clean && make -j 256 ; done

How's it doin'?  Nice of you to ask.  About like this:

# free
             total       used       free     shared    buffers   cached
Mem:       1556276    1515096      41180          0       1644   26752
-/+ buffers/cache:    1486700      69576
Swap:      1469820     249480    1220340

# uptime 
 22:33:15 up  5:06,  3 users,  load average: 305.90, 308.94, 304.04

#  ps auxw | wc -l
1098

# vmstat 4
procs -----------memory---------- ---swap-- -----io---- -system-- 
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs 
285 10 337012 110908   1968  27516  785 1032   838  1078  302  138
350 11 324944 137436   1968  27704 2425    0  2446    63  354  239
351 23 317644 156884   1980  27860  511    0   529     9  278  174
337 22 315668 158884   1984  28048  466    0   490    17  277  129
338 11 306500 183596   1992  28144 2340    0  2349     4  349  247

Dunno about you, but that puppy strikes me as a bit _busy_.  ;->