Hi,
I have an AlphaServer 1000A running Digital Unix 4.0B with 192M of memory.
There is currently about 1500 users. The system is used mostly by
students, but also faculty and staff can have accounts. It is used mostly
for programming (C, C++ , Fortran, Lisp), Web pages, pine, trn.
The problem: Some of my users complain that the system hangs or pauses for
about 1 minute when they are on the system and then will pick up again. I
have searched the archives and have found some tuning suggestions. I
implemented these, but they did not help. It seems to me that the system
has a low free memory problem. But, I am not sure I am reading the data
correctly.
Using suggestions from the Web Server Tuning Guide and posts from the
archive I have set the following (and rebooted):
I moved /sbin/swapdefault to /sbin/swapdefault.disabled
Changes to /etc/sysconfigtab:
proc:
max-proc-per-user=512
max-threads-per-user=4096
maxusers=512
vm:
ubc-maxpercent=50
vm-page-free-min=50
vm-page-free-target=400
vm-mapentries=20000
inet:
tcbhashsize=1024
tcp_rexmit_interval_min=128
socket:
somaxconn=32767
sominconn=32767
vfs:
bufcache=1
Statistics display as:
# uptime
10:11 up 15 days, 19 mins, 25 users, load average: 0.10, 0.04,
0.04
# vmstat 1 5
Virtual Memory Statistics: (pagesize = 8192)
procs memory
pages intr cpu
r w u act free
wire fault cow zero react pin pout in sy cs us sy id
3164 22 16K
999 5390 200M 62M 70M 208K 96M 6307 46 4K 350 46 8 46
2165 22
16K 758 5391 467 13 413 0 26 0 204 1K 442 3 11 86
2165
22 16K 758 5391 176 0 162 0 11 0 68 275 337 1 8 90
5162 22 16K 754 5395 164 0 162 0 2 0 44 86 362 1 8
91
2165 22 16K 757 5392 165 0 162 0 1 0 83 435 362 2
9 90
# swapon -s
Swap partition /dev/rz0b:
Allocated space: 25000
pages (195MB)
In-use space: 940 pages ( 3%)
Free
space: 24060 pages ( 96%)
Swap partition /dev/rz1h:
Allocated space: 25000 pages (195MB)
In-use space:
936 pages ( 3%)
Free space: 24064 pages ( 96%)
Swap
partition /dev/rz2h:
Allocated space: 25000 pages (195MB)
In-use space: 926 pages ( 3%)
Free space:
24074 pages ( 96%)
Total swap allocation:
Allocated space:
75000 pages (585MB)
In-use space: 2802 pages ( 3%)
Available space: 72198 pages ( 96%)
#
Unicensus (sys_check) suggests the following changes for my system which I
have not implemented yet:
vm:
new-wire-method=0
vm-ubcseqpercent=20
name-cache-hash-size=512
vm-vpagemax=65536
advfs:
AdvfsCacheMaxPercent=9
AdvfsMaxDecQLen=16
setting MTU to 4136
The free memory from vmstat does drop below 100 at times. Does the system
simply need more memory? How can I list what processes are using the
memory? Is there any tool to show memory usage by process (besides ps)?
If not, what column in a ps listing shows memory usage?
Any guidance is welcome.
Ellen Davis
Ellen.Davis_at_uc.edu
Received on Wed May 06 1998 - 17:35:05 NZST