QUESTION:
Customer is running AIX 3.2.1 and a group of PS/2 accessing the dos
server function using AADU 2.1 on a 16Mb T/R. DOS server is the only
function that customer uses from the RS/6000. Is there any parameter
that I can help customer to tune to make the DOS server run fast?
---------- ---------- ---------- --------- ---------- ----------
A: Customers have previously acknowledged an increase in Token Ring
performance by resetting the token ring IRQ value to 3. Other than
that suggestion, we know of no parameter than can be tuned to make the
DOS server run fast.
You did not really mention that your customer was experiencing slow
performance using AADU. However, our database does show previous reports
involving AADU 2.1 and slow performance. If this has been a problem
for your customer, you may want to contact Software Services at
1-800-237-5511 to request the fix for this situation, when available.
Please be sure to mention APAR IX21229.
---------- ---------- ---------- --------- ---------- ----------
QUESTION:
Would you please explain to me how is the I/O being performed on the
virtual drive? Is the mbuf being used? Will a larger mbuf help the
performance? I have talked to the defect support for another matter,
defect support told me that performance is an ASKQ issue. Performance in
this customer's environment is no different from my other customer's.
But since DOS server function is the only task running in the RS/6000.
I would like to know how to use the extra memory and cpu in the box.
---------- ---------- ---------- --------- ---------- ----------
A: All I/O done to support AADU, including remote file service on both
on the server and client side, uses the Internet Protocol (IP). The
AIX implementation of IP uses mbufs to do I/O. The main
consideration in the relationship of mbufs to IP performance is
whether IP has been denied a request for mbufs. The AIX command
"netstat -m" will give information about mbufs. Example output of
"netstat -m":
$ netstat -m
224/480 mbufs in use:
17 mbufs allocated to data
16 mbufs allocated to packet headers
70 mbufs allocated to socket structures
107 mbufs allocated to protocol control blocks
5 mbufs allocated to routing table entries
7 mbufs allocated to socket names and addresses
2 mbufs allocated to interface addresses
16/49 mapped pages in use
256 Kbytes allocated to network (35% in use)
0 requests for memory denied
The last line of the output gives the number of denied requests for
memory. If this number is 0, then you have sufficient mbufs and more
will not increase IP performance. If, however, the number is
greater then 0, then IP has been unable to get mbufs, which has a
negative impact on performance. The "no" command can be used to
determine the current mbuf allocation and increase it. "no -a"
gives network interface information. Example
output of "no -a":
$ no -a
dog_ticks = 60
lowclust = 26
lowmbuf = 88
thewall = 2000
subnetsarelocal = 1
maxttl = 255
ipfragttl = 60
ipsendredirects = 1
ipforwarding = 1
udp_ttl = 30
tcp_ttl = 30
arpt_killc = 20
tcp_sendspace = 4096
tcp_recvspace = 4096
loop_check_sum = 1
udp_sendspace = 2048
udp_recvspace = 4160
The property that corresponds to the mbuf allocation is "thewall".
In the example output, thewall = 2000, which corresponds to an mbuf
allocation of 2 Meg. If netstat -m shows that requests for mbufs
have been denied, then "no -o thewall=3000" would increase mbufs to 3
Meg, which should prevent requests for mbufs from being denied.
In general, since AADU runs over IP, tuning IP on the AIX Dos server
side could benefit AADU performance.
---------- ---------- ---------- --------- ---------- ----------
This item was created from library item Q600586 BQNXP
Additional search words:
AADU BQNXP DOS FAST IX OP PERFORMANCE RISCOSO RISCSYSTEM SEP92 SERVE
SERVER SOFTWARE SYS TUNE TUNING
WWQA: ITEM: RTA000025678 ITEM: RTA000025678
Dated: 11/1996 Category: RISCOSO
This HTML file was generated 99/06/24~12:43:09
Comments or suggestions?
Contact us