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The no command
The no (network options) command is used to set network tuning parameters.
Use the no command to configure network tuning parameters. The no command sets or displays current or next boot values for network tuning parameters. This command can also make permanent changes or defer changes until the next reboot. Whether the command sets or displays a parameter is determined by the accompanying flag. The -o flag performs both actions. It can either display the value of a parameter or set a new value for a parameter. When the no command is used to modify a network option it logs a message to the syslog using the LOG_KERN facility.
| no [ -p | -r ] { -o Tunable[=NewValue] } |
| no [ -p | -r ] {-d Tunable } |
| no [ -p | -r ] { -D } |
| no [ -p | -r ] -a |
| no -? |
| no -h [ Tunable ] |
| no -L [ Tunable ] |
| no -x [ Tunable ] Note: Multiple flags -o, -d, -x, and -L are allowed. |
The no command in located in /usr/sbin/no and is part of the bos.net.tcp.client fileset. This fileset is installed by default at installation time.
Be careful when you use this command. If used incorrectly, the no command can cause your system to become inoperable.
Before modifying any tunable parameter, you should first carefully read about all its characteristics of a tunable. For more information about tunable parameters, see Network Tunable Parameters in the man pages
You must then make sure that the Diagnosis and Tuning sections for this parameter truly apply to your situation and that changing the value of this parameter could help improve the performance of your system.
A list of all the available tunables can be displayed with the no -a command as in Example 6-60.
Example 6-60 The no -a example
[p630n04][/home/hennie]> no -a
arpqsize = 12
arpt_killc = 20
arptab_bsiz = 7
arptab_nb = 73
bcastping = 0
clean_partial_conns = 0
delayack = 0
delayackports = {}
dgd_packets_lost = 3
dgd_ping_time = 5
dgd_retry_time = 5
directed_broadcast = 0
extendednetstats = 1
fasttimo = 200
icmp6_errmsg_rate = 10
icmpaddressmask = 0
ie5_old_multicast_mapping = 0
ifsize = 256
inet_stack_size = 16
ip6_defttl = 64
ip6_prune = 1
ip6forwarding = 0
ip6srcrouteforward = 1
ipforwarding = 1
ipfragttl = 60
ipignoreredirects = 0
ipqmaxlen = 100
ipsendredirects = 1
ipsrcrouteforward = 1
ipsrcrouterecv = 1
ipsrcroutesend = 1
llsleep_timeout = 3
lowthresh = 90
main_if6 = 0
main_site6 = 0
maxnip6q = 20
maxttl = 255
medthresh = 95
mpr_policy = 1
multi_homed = 1
nbc_limit = 891289
nbc_max_cache = 131072
nbc_min_cache = 1
nbc_ofile_hashsz = 12841
nbc_pseg = 0
nbc_pseg_limit = 4194304
ndd_event_name = {all}
ndd_event_tracing = 0
ndp_mmaxtries = 3
ndp_umaxtries = 3
ndpqsize = 50
ndpt_down = 3
ndpt_keep = 120
ndpt_probe = 5
ndpt_reachable = 30
ndpt_retrans = 1
net_buf_size = {all}
net_buf_type = {all}
net_malloc_police = 0
nonlocsrcroute = 1
nstrpush = 8
passive_dgd = 0
pmtu_default_age = 10
pmtu_expire = 10
pmtu_rediscover_interval = 30
psebufcalls = 20
psecache = 1
pseintrstack = 12288
psetimers = 20
rfc1122addrchk = 0
rfc1323 = 0
rfc2414 = 0
route_expire = 1
routerevalidate = 0
rto_high = 64
rto_length = 13
rto_limit = 7
rto_low = 1
sack = 0
sb_max = 1048576
send_file_duration = 300
site6_index = 0
sockthresh = 75
sodebug = 0
somaxconn = 1024
strctlsz = 1024
strmsgsz = 0
strthresh = 85
strturncnt = 15
subnetsarelocal = 1
tcp_bad_port_limit = 0
tcp_ecn = 0
tcp_ephemeral_high = 65535
tcp_ephemeral_low = 32768
tcp_finwait2 = 1200
tcp_init_window = 0
tcp_inpcb_hashtab_siz = 24499
tcp_keepcnt = 8
tcp_keepidle = 14400
tcp_keepinit = 150
tcp_keepintvl = 150
tcp_limited_transmit = 1
tcp_maxburst = 0
tcp_mssdflt = 1460
tcp_nagle_limit = 65535
tcp_ndebug = 100
tcp_newreno = 1
tcp_nodelayack = 0
tcp_pmtu_discover = 1
tcp_recvspace = 16384
tcp_sendspace = 16384
tcp_timewait = 1
tcp_ttl = 60
thewall = 1048576
udp_bad_port_limit = 0
udp_ephemeral_high = 65535
udp_ephemeral_low = 32768
udp_inpcb_hashtab_siz = 24499
udp_pmtu_discover = 1
udp_recvspace = 42080
udp_sendspace = 9216
udp_ttl = 30
udpcksum = 1
use_isno = 1
use_sndbufpool = 1
[p630n04][/home/hennie]>
The no -o command is used to display or set a specific tunable.In Example 6-61 the no -o command is used to display the tunable value of tcp_recvspace.
Example 6-61 The no -o example to display a tunable
[p630n04][/home/hennie]> no -o tcp_recvspace
tcp_recvspace = 16384
[p630n04][/home/hennie]>
When changing the value of a tunable make sure you understand the characteristics of the tunable.
The no -L command can be used to display the values associated with the tunables. All the tunables can be listed with its attributes or a particular tunable can be displayed.
To display all the attributes associated with the no command use no -L with no arguments as in Example 6-62.
Example 6-62 The no -L command
[p630n04][/home/hennie]> no -L
General Network Parameters
----------------------------------------------------------------------------------------------
NAME CUR DEF BOOT MIN MAX UNIT TYPE
DEPENDENCIES
----------------------------------------------------------------------------------------------
extendednetstats 1 0 0 0 1 boolean R
----------------------------------------------------------------------------------------------
fasttimo 200 200 200 50 200 millisecond D
----------------------------------------------------------------------------------------------
inet_stack_size 16 16 16 1 32K-1 kbyte R
----------------------------------------------------------------------------------------------
nbc_limit 891289 891289 891289 0 2G-1 kbyte D
thewall
----------------------------------------------------------------------------------------------
nbc_max_cache 128K 128K 128K 1 2G-1 byte D
nbc_min_cache
----------------------------------------------------------------------------------------------
nbc_min_cache 1 1 1 1 128K byte D
nbc_max_cache
----------------------------------------------------------------------------------------------
nbc_ofile_hashsz 12841 12841 12841 1 999999 segment D
----------------------------------------------------------------------------------------------
nbc_pseg 0 0 0 0 2G-1 segment D
----------------------------------------------------------------------------------------------
nbc_pseg_limit 4M 4M 4M 0 2G-1 kbyte D
----------------------------------------------------------------------------------------------
ndd_event_name {all} {all} {all} 0 128 string D
----------------------------------------------------------------------------------------------
ndd_event_tracing 0 0 0 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
net_buf_size {all} {all} {all} 0 128 string D
----------------------------------------------------------------------------------------------
net_buf_type {all} {all} {all} 0 128 string D
----------------------------------------------------------------------------------------------
net_malloc_police 0 0 0 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
sb_max 1M 1M 1M 1 2G-1 byte D
----------------------------------------------------------------------------------------------
send_file_duration 300 300 300 0 2G-1 second D
----------------------------------------------------------------------------------------------
sockthresh 75 85 85 0 100 %_of_thewall D
----------------------------------------------------------------------------------------------
sodebug 0 0 0 0 1 boolean C
----------------------------------------------------------------------------------------------
somaxconn 1K 1K 1K 0 32K-1 numeric C
----------------------------------------------------------------------------------------------
tcp_inpcb_hashtab_siz 24499 24499 24499 1 999999 numeric R
----------------------------------------------------------------------------------------------
thewall 1M 1M 1M 0 1M kbyte S
----------------------------------------------------------------------------------------------
udp_inpcb_hashtab_siz 24499 24499 24499 1 83000 numeric R
----------------------------------------------------------------------------------------------
use_isno 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
use_sndbufpool 1 1 1 0 1 boolean R
----------------------------------------------------------------------------------------------
clean_partial_conns 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
delayack 0 0 0 0 3 boolean D
----------------------------------------------------------------------------------------------
delayackports {} {} {} 0 10 ports_list D
----------------------------------------------------------------------------------------------
rfc1323 0 0 0 0 1 boolean C
----------------------------------------------------------------------------------------------
rfc2414 0 0 0 0 1 boolean C
----------------------------------------------------------------------------------------------
rto_high 64 64 64 2 2G-1 roundtriptime R
rto_low
----------------------------------------------------------------------------------------------
rto_length 13 13 13 1 64 roundtriptime R
----------------------------------------------------------------------------------------------
rto_limit 7 7 7 1 64 roundtriptime R
rto_high
rto_low
----------------------------------------------------------------------------------------------
rto_low 1 1 1 1 63 roundtriptime R
rto_high
----------------------------------------------------------------------------------------------
sack 0 0 0 0 1 boolean C
----------------------------------------------------------------------------------------------
tcp_bad_port_limit 0 0 0 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
tcp_ecn 0 0 0 0 1 boolean C
----------------------------------------------------------------------------------------------
tcp_ephemeral_high 64K-1 64K-1 64K-1 32K+1 64K-1 numeric D
tcp_ephemeral_low
----------------------------------------------------------------------------------------------
tcp_ephemeral_low 32K 32K 32K 1K 65534 numeric D
tcp_ephemeral_high
----------------------------------------------------------------------------------------------
tcp_finwait2 1200 1200 1200 0 64K-1 halfsecond D
----------------------------------------------------------------------------------------------
tcp_init_window 0 0 0 0 32K-1 byte C
----------------------------------------------------------------------------------------------
tcp_keepcnt 8 8 8 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
tcp_keepidle 14400 14400 14400 1 2G-1 halfsecond C
----------------------------------------------------------------------------------------------
tcp_keepinit 150 150 150 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
tcp_keepintvl 150 150 150 1 32K-1 halfsecond C
----------------------------------------------------------------------------------------------
tcp_limited_transmit 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
tcp_maxburst 0 0 0 0 32K-1 numeric D
----------------------------------------------------------------------------------------------
tcp_mssdflt 1460 1460 1460 1 64K-1 byte C
----------------------------------------------------------------------------------------------
tcp_nagle_limit 64K-1 64K-1 64K-1 0 64K-1 byte D
----------------------------------------------------------------------------------------------
tcp_ndebug 100 100 100 0 32K-1 numeric D
----------------------------------------------------------------------------------------------
tcp_newreno 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
tcp_nodelayack 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
tcp_recvspace 16K 16K 16K 4K 2G-1 byte C
sb_max
----------------------------------------------------------------------------------------------
tcp_sendspace 16K 16K 16K 4K 2G-1 byte C
sb_max
----------------------------------------------------------------------------------------------
tcp_timewait 1 1 1 1 5 15_second D
----------------------------------------------------------------------------------------------
tcp_ttl 60 60 60 1 255 0.6_second C
----------------------------------------------------------------------------------------------
udp_bad_port_limit 0 0 0 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
udp_ephemeral_high 64K-1 64K-1 64K-1 32K+1 64K-1 numeric D
udp_ephemeral_low
----------------------------------------------------------------------------------------------
udp_ephemeral_low 32K 32K 32K 1K 65534 numeric D
udp_ephemeral_high
----------------------------------------------------------------------------------------------
udp_recvspace 42080 42080 42080 4K 2G-1 byte C
sb_max
----------------------------------------------------------------------------------------------
udp_sendspace 9K 9K 9K 4K 2G-1 byte C
sb_max
----------------------------------------------------------------------------------------------
udp_ttl 30 30 30 1 255 second C
----------------------------------------------------------------------------------------------
udpcksum 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
directed_broadcast 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ie5_old_multicast_mapping 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ip6_defttl 64 64 64 1 255 numeric D
----------------------------------------------------------------------------------------------
ip6_prune 1 1 1 1 2G-1 second D
----------------------------------------------------------------------------------------------
ip6forwarding 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ip6srcrouteforward 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
ipforwarding 1 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ipfragttl 60 60 60 1 255 halfsecond D
----------------------------------------------------------------------------------------------
ipignoreredirects 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ipqmaxlen 100 100 100 100 2G-1 numeric R
----------------------------------------------------------------------------------------------
ipsendredirects 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
ipsrcrouteforward 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
ipsrcrouterecv 1 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ipsrcroutesend 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
maxnip6q 20 20 20 1 32K-1 numeric D
----------------------------------------------------------------------------------------------
multi_homed 1 1 1 0 3 boolean D
----------------------------------------------------------------------------------------------
nonlocsrcroute 1 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
subnetsarelocal 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
arpqsize 12 12 12 1 32K-1 numeric D
tcp_pmtu_discover
udp_pmtu_discover
----------------------------------------------------------------------------------------------
arpt_killc 20 20 20 0 32K-1 minute D
----------------------------------------------------------------------------------------------
arptab_bsiz 7 7 7 1 32K-1 bucket_size R
----------------------------------------------------------------------------------------------
arptab_nb 73 73 73 1 32K-1 buckets R
----------------------------------------------------------------------------------------------
dgd_packets_lost 3 3 3 1 32K-1 numeric D
----------------------------------------------------------------------------------------------
dgd_ping_time 5 5 5 1 2G-1 second D
----------------------------------------------------------------------------------------------
dgd_retry_time 5 5 5 1 32K-1 numeric D
----------------------------------------------------------------------------------------------
ndp_mmaxtries 3 3 3 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
ndp_umaxtries 3 3 3 0 2G-1 numeric D
----------------------------------------------------------------------------------------------
ndpqsize 50 50 50 1 32K-1 numeric D
----------------------------------------------------------------------------------------------
ndpt_down 3 3 3 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
ndpt_keep 120 120 120 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
ndpt_probe 5 5 5 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
ndpt_reachable 30 30 30 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
ndpt_retrans 1 1 1 1 2G-1 halfsecond D
----------------------------------------------------------------------------------------------
passive_dgd 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
rfc1122addrchk 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
lowthresh 90 90 90 0 100 %_of_thewall D
----------------------------------------------------------------------------------------------
medthresh 95 95 95 0 100 %_of_thewall D
----------------------------------------------------------------------------------------------
nstrpush 8 8 8 8 32K-1 numeric R
----------------------------------------------------------------------------------------------
psebufcalls 20 20 20 20 2G-1 numeric I
----------------------------------------------------------------------------------------------
psecache 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
pseintrstack 12K 12K 12K 12K 2G-1 byte R
----------------------------------------------------------------------------------------------
psetimers 20 20 20 20 2G-1 numeric I
----------------------------------------------------------------------------------------------
strctlsz 1K 1K 1K 0 32K-1 byte D
----------------------------------------------------------------------------------------------
strmsgsz 0 0 0 0 32K-1 byte D
----------------------------------------------------------------------------------------------
strthresh 85 85 85 0 100 %_of_thewall D
----------------------------------------------------------------------------------------------
strturncnt 15 15 15 1 2G-1 numeric D
----------------------------------------------------------------------------------------------
bcastping 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
icmp6_errmsg_rate 10 10 10 1 255 msg/second D
----------------------------------------------------------------------------------------------
icmpaddressmask 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
ifsize 256 256 256 8 1K numeric R
----------------------------------------------------------------------------------------------
llsleep_timeout 3 3 3 1 2G-1 second D
----------------------------------------------------------------------------------------------
main_if6 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
main_site6 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
maxttl 255 255 255 1 255 second D
----------------------------------------------------------------------------------------------
mpr_policy 1 1 1 1 5 numeric D
----------------------------------------------------------------------------------------------
pmtu_default_age 10 10 10 0 32K-1 minute D
----------------------------------------------------------------------------------------------
pmtu_expire 10 10 10 0 32K-1 minute D
----------------------------------------------------------------------------------------------
pmtu_rediscover_interval 30 30 30 0 32K-1 minute D
----------------------------------------------------------------------------------------------
route_expire 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
routerevalidate 0 0 0 0 1 boolean D
----------------------------------------------------------------------------------------------
site6_index 0 0 0 0 32K-1 numeric D
----------------------------------------------------------------------------------------------
tcp_pmtu_discover 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
udp_pmtu_discover 1 1 1 0 1 boolean D
----------------------------------------------------------------------------------------------
n/a means parameter not supported by the current platform or kernel
Parameter types:
S = Static: cannot be changed
D = Dynamic: can be freely changed
B = Bosboot: can only be changed using bosboot and reboot
R = Reboot: can only be changed during reboot
C = Connect: changes are only effective for future socket connections
M = Mount: changes are only effective for future mountings
I = Incremental: can only be incremented
Value conventions:
K = Kilo: 2^10 G = Giga: 2^30 P = Peta: 2^50
M = Mega: 2^20 T = Tera: 2^40 E = Exa: 2^60
[p630n04][/home/hennie]>
As can be seen in Example 6-62 the no -L command displays a list of all the tunables and detail about the value of each tunable.
The fields displayed by the no -L command are:
| NAME This displays the name of the tunable |
| CUR This displays the current value of the tunable |
| DEF This displays the default value of the tunable |
| BOOT This displays the value of the tunable after a reboot. |
| MIN This displays the minimum value of the tunable |
| MAX This displays the maximum value of the tunable. |
| UNIT This displays the tunables unit of measurement |
| TYPE This displays the parameter type. The parameter type specifies how a particular tunable change will take effect. |
| D - Dynamic, the tunable value is a dynamic value and a change to the tunable will take effect immediately. |
| S - Static, the tunable is a static value and the value of the tunable cannot be changed. |
| R - Reboot, the tunable value is a reboot value and the tunable change will only take effect after a reboot. |
| B - Bosboot, the tunable value is a bosboot value and the user needs to run the bosboot command for the BLV (Boot logical volume) to be updated. Changes will only take effect after a reboot. |
| M - Mount, the value of the tunable is a mount value and the tunable will only take effect after the file system is remounted or new mounts occur on a file system. |
| I - Incremental, the value of the tunable is incremental and can only be incremented, except at boot time. |
| C - Connect, the value of the tunable is connection orientated, the tunable will only take effect for new socket connections. |
| DEPENDENCIES This displays a list of dependable tunables, it will display one dependency per line. |
To display the attributes associated with particular tunable see Example 6-63. This example displays the output of the no -L command to display the value attributes associated with the tcp_recvspace tunable.
Example 6-63 The no -L tcp_recvspace
[p630n04][/home/hennie]> no -L tcp_recvspace
----------------------------------------------------------------------------------------------
NAME CUR DEF BOOT MIN MAX UNIT TYPE
DEPENDENCIES
----------------------------------------------------------------------------------------------
tcp_recvspace 32K 16K 16K 4K 2G-1 byte C
sb_max
----------------------------------------------------------------------------------------------
[p630n04][/home/hennie]>
The no -x command gives the same information as the no -L command, it just displays the information of each tunable in a comma separated list. See Example 6-64.
Example 6-64 The no -x command
[p630n04][/]> no -x
arpqsize,12,12,12,1,32767,numeric,D,tcp_pmtu_discover,udp_pmtu_discover,
arpt_killc,20,20,20,0,32767,minute,D,
arptab_bsiz,7,7,7,1,32767,bucket_size,R,
arptab_nb,73,73,73,1,32767,buckets,R,
bcastping,0,0,0,0,1,boolean,D,
clean_partial_conns,0,0,0,0,1,boolean,D,
delayack,0,0,0,0,3,boolean,D,
delayackports,{},{},{},0,10,ports_list,D,
dgd_packets_lost,3,3,3,1,32767,numeric,D,
dgd_ping_time,5,5,5,1,2147483647,second,D,
dgd_retry_time,5,5,5,1,32767,numeric,D,
directed_broadcast,0,0,0,0,1,boolean,D,
extendednetstats,1,0,0,0,1,boolean,R,
fasttimo,200,200,200,50,200,millisecond,D,
icmp6_errmsg_rate,10,10,10,1,255,msg/second,D,
icmpaddressmask,0,0,0,0,1,boolean,D,
ie5_old_multicast_mapping,0,0,0,0,1,boolean,D,
ifsize,256,256,256,8,1024,numeric,R,
inet_stack_size,16,16,16,1,32767,kbyte,R,
ip6_defttl,64,64,64,1,255,numeric,D,
ip6_prune,1,1,1,1,2147483647,second,D,
ip6forwarding,0,0,0,0,1,boolean,D,
ip6srcrouteforward,1,1,1,0,1,boolean,D,
ipforwarding,1,0,0,0,1,boolean,D,
ipfragttl,60,60,60,1,255,halfsecond,D,
ipignoreredirects,0,0,0,0,1,boolean,D,
ipqmaxlen,100,100,100,100,2147483647,numeric,R,
ipsendredirects,1,1,1,0,1,boolean,D,
ipsrcrouteforward,1,1,1,0,1,boolean,D,
ipsrcrouterecv,1,0,0,0,1,boolean,D,
ipsrcroutesend,1,1,1,0,1,boolean,D,
llsleep_timeout,3,3,3,1,2147483647,second,D,
lowthresh,90,90,90,0,100,%_of_thewall,D,
main_if6,0,0,0,0,1,boolean,D,
main_site6,0,0,0,0,1,boolean,D,
maxnip6q,20,20,20,1,32767,numeric,D,
maxttl,255,255,255,1,255,second,D,
medthresh,95,95,95,0,100,%_of_thewall,D,
mpr_policy,1,1,1,1,5,numeric,D,
multi_homed,1,1,1,0,3,boolean,D,
nbc_limit,891289,891289,891289,0,2147483647,kbyte,D,thewall,
nbc_max_cache,131072,131072,131072,1,2147483647,byte,D,nbc_min_cache,
nbc_min_cache,1,1,1,1,131072,byte,D,nbc_max_cache,
nbc_ofile_hashsz,12841,12841,12841,1,999999,segment,D,
nbc_pseg,0,0,0,0,2147483647,segment,D,
nbc_pseg_limit,4194304,4194304,4194304,0,2147483647,kbyte,D,
ndd_event_name,{all},{all},{all},0,128,string,D,
ndd_event_tracing,0,0,0,0,2147483647,numeric,D,
ndp_mmaxtries,3,3,3,0,2147483647,numeric,D,
ndp_umaxtries,3,3,3,0,2147483647,numeric,D,
ndpqsize,50,50,50,1,32767,numeric,D,
ndpt_down,3,3,3,1,2147483647,halfsecond,D,
ndpt_keep,120,120,120,1,2147483647,halfsecond,D,
ndpt_probe,5,5,5,1,2147483647,halfsecond,D,
ndpt_reachable,30,30,30,1,2147483647,halfsecond,D,
ndpt_retrans,1,1,1,1,2147483647,halfsecond,D,
net_buf_size,{all},{all},{all},0,128,string,D,
net_buf_type,{all},{all},{all},0,128,string,D,
net_malloc_police,0,0,0,0,2147483647,numeric,D,
nonlocsrcroute,1,0,0,0,1,boolean,D,
nstrpush,8,8,8,8,32767,numeric,R,
passive_dgd,0,0,0,0,1,boolean,D,
pmtu_default_age,10,10,10,0,32767,minute,D,
pmtu_expire,10,10,10,0,32767,minute,D,
pmtu_rediscover_interval,30,30,30,0,32767,minute,D,
psebufcalls,20,20,20,20,2147483647,numeric,I,
psecache,1,1,1,0,1,boolean,D,
pseintrstack,12288,12288,12288,12288,2147483647,byte,R,
psetimers,20,20,20,20,2147483647,numeric,I,
rfc1122addrchk,0,0,0,0,1,boolean,D,
rfc1323,0,0,0,0,1,boolean,C,
rfc2414,0,0,0,0,1,boolean,C,
route_expire,1,1,1,0,1,boolean,D,
routerevalidate,0,0,0,0,1,boolean,D,
rto_high,64,64,64,2,2147483647,roundtriptime,R,rto_low,
rto_length,13,13,13,1,64,roundtriptime,R,
rto_limit,7,7,7,1,64,roundtriptime,R,rto_high,rto_low,
rto_low,1,1,1,1,63,roundtriptime,R,rto_high,
sack,0,0,0,0,1,boolean,C,
sb_max,1048576,1048576,1048576,1,2147483647,byte,D,
send_file_duration,300,300,300,0,2147483647,second,D,
site6_index,0,0,0,0,32767,numeric,D,
sockthresh,75,85,85,0,100,%_of_thewall,D,
sodebug,0,0,0,0,1,boolean,C,
somaxconn,1024,1024,1024,0,32767,numeric,C,
strctlsz,1024,1024,1024,0,32767,byte,D,
strmsgsz,0,0,0,0,32767,byte,D,
strthresh,85,85,85,0,100,%_of_thewall,D,
strturncnt,15,15,15,1,2147483647,numeric,D,
subnetsarelocal,1,1,1,0,1,boolean,D,
tcp_bad_port_limit,0,0,0,0,2147483647,numeric,D,
tcp_ecn,0,0,0,0,1,boolean,C,
tcp_ephemeral_high,65535,65535,65535,32769,65535,numeric,D,tcp_ephemeral_low,
tcp_ephemeral_low,32768,32768,32768,1024,65534,numeric,D,tcp_ephemeral_high,
tcp_finwait2,1200,1200,1200,0,65535,halfsecond,D,
tcp_init_window,0,0,0,0,32767,byte,C,
tcp_inpcb_hashtab_siz,24499,24499,24499,1,999999,numeric,R,
tcp_keepcnt,8,8,8,0,2147483647,numeric,D,
tcp_keepidle,14400,14400,14400,1,2147483647,halfsecond,C,
tcp_keepinit,150,150,150,1,2147483647,halfsecond,D,
tcp_keepintvl,150,150,150,1,32767,halfsecond,C,
tcp_limited_transmit,1,1,1,0,1,boolean,D,
tcp_maxburst,0,0,0,0,32767,numeric,D,
tcp_mssdflt,1460,1460,1460,1,65535,byte,C,
tcp_nagle_limit,65535,65535,65535,0,65535,byte,D,
tcp_ndebug,100,100,100,0,32767,numeric,D,
tcp_newreno,1,1,1,0,1,boolean,D,
tcp_nodelayack,0,0,0,0,1,boolean,D,
tcp_pmtu_discover,1,1,1,0,1,boolean,D,
tcp_recvspace,16384,16384,16k,4096,2147483647,byte,C,sb_max,
tcp_sendspace,16384,16384,16384,4096,2147483647,byte,C,sb_max,
tcp_timewait,1,1,1,1,5,15_second,D,
tcp_ttl,60,60,60,1,255,0.6_second,C,
thewall,1048576,1048576,1048576,0,1048576,kbyte,S,
udp_bad_port_limit,0,0,0,0,2147483647,numeric,D,
udp_ephemeral_high,65535,65535,65535,32769,65535,numeric,D,udp_ephemeral_low,
udp_ephemeral_low,32768,32768,32768,1024,65534,numeric,D,udp_ephemeral_high,
udp_inpcb_hashtab_siz,24499,24499,24499,1,83000,numeric,R,
udp_pmtu_discover,1,1,1,0,1,boolean,D,
udp_recvspace,42080,42080,42080,4096,2147483647,byte,C,sb_max,
udp_sendspace,9216,9216,9216,4096,2147483647,byte,C,sb_max,
udp_ttl,30,30,30,1,255,second,C,
udpcksum,1,1,1,0,1,boolean,D,
use_isno,1,1,1,0,1,boolean,D,
use_sndbufpool,1,1,1,0,1,boolean,R,
[p630n04][/]>
To display a specific tunable using the no -x command see Example 6-65.
Example 6-65 The no -x tcp_recvspace
[p630n04][/]> no -x tcp_recvspace
tcp_recvspace,16384,16384,16k,4096,2147483647,byte,C,sb_max,
[p630n04][/]>
The output of the no -x command lists the following attributes. "tunable, current, default, reboot, min, max, unit, type" in a comma separated list.
As can be seen from the output the command the current value of the tunable is 32K, the default value is 16K, the minimum value is 4K, the maximum value is 2G-1. The unit used for this tunable is bytes, and the tunable type is C (Connect), which means if the tunable is changed the changes will only take effect for new connections. This tunable is also dependent on the sb_max tunable.
To better understand what a specific tunable is used for you can use the no -h command to display a description of the tunable. As can be seen in Example 6-66 a very detailed explanation is given about the tcp_recvspace tunable, when using the no -h option.
Example 6-66 The no -h example
[p630n04][/home/hennie]> no -h tcp_recvspace
Help for tunable tcp_recvspace:
Specifies the system default socket buffer size for receiving data. This affects the window size used by TCP. Setting the socket buffer size to 16KB (16,384) improves performance over Standard Ethernet and token-ring networks. The default is a value of 4096; however, a value of 16,384 is set automatically by the rc.net file or the rc.bsdnet file (if Berkeley-style configuration is issued). Lower bandwidth networks, such as Serial Line Internet Protocol (SLIP), or higher bandwidth networks, such as Serial Optical Link, should have different optimum buffer sizes. The optimum buffer size is the product of the media bandwidth and the average round-trip time of a packet. In AIX 4.3.3 and later versions, the tcp_recvspace network option can also be set on a per interface basis via the ifconfig command. The tcp_recvspace attribute must specify a socket buffer size less than or equal to the setting of the sb_max attribute. tcp_recvspace is a Connect attribute, but for daemons started by inetd, the following command needs to be executed: 'stopsrc -s inetd ; startsrc -s inetd'
To change the value of a tunable with no -o see Example 6-67. The no -o command is used to change the value of the tcp_recvspace to 32768.
Example 6-67 The no -o
[p630n04][/home/hennie]> no -o tcp_recvspace=32768
Setting tcp_recvspace to 32768
Change to tunable tcp_recvspace, will only be effective for future connections
[p630n04][/home/hennie]>
All tunables set by the no -o command is only valid for the duration that the system is up. If the system is rebooted it automatically uses the default values of the tunables.
AIX 5.2 introduced a more flexible and centralized mode for setting most of the AIX kernel tuning parameters. It is now possible to make permanent changes without editing any rc files. This is achieved by placing the reboot values for all tunable parameters in a new /etc/tunables/nextboot stanza file. When the machine is rebooted, the values in that file are automatically applied.
The /etc/tunables/lastboot stanza file is automatically generated with all the values that were set immediately after the reboot. This provides the ability to return to those values at any time. The /etc/tunables/lastboot.log log file records any changes made or that could not be made during reboot. There are sets of SMIT panels and a Web-based System Manager plug-in also available to manipulate current and reboot values for all tuning parameters, as well as the files in the /etc/tunables directory.
Pre 5.2 compatibility mode is controlled by the pre520tune attribute of sys0. When running in pre 5.2 compatibility mode, reboot values for parameters, except those of type Bosboot, are not really meaningful because in this mode they are not applied at boot time.
In pre 5.2 compatibility mode, setting reboot values to tuning parameters continues to be achieved by imbedding calls to tuning commands in rc scripts called during the boot sequence. Parameters of type Reboot can therefore be set without the -r flag, so that existing scripts continue to work.
This mode is automatically turned ON when a machine is MIGRATED to AIX 5L Version 5.2. For complete installations, it is turned OFF and the reboot values for parameters are set by applying the content of the /etc/tunables/nextboot file during the reboot sequence. Only in that mode are the -r and -p flags fully functional.
The following commands were introduced in AIX 5.2 to modify the tunables files (see Table 6-2).
Table 6-2
|
Command
|
Purpose
|
|---|---|
|
tunsave
|
Saves values to a stanza file
|
|
tunrestore
|
Applies applicable parameter values that are specified in a file
|
|
tuncheck
|
Validates files that are created manually
|
|
tundefault
|
Resets tunable parameters to their default values
|
AIX 5.2 Tunables commands
To make any changes to no tunables be effective after a reboot the -r or -p commands can be used.
When using the -r option with the no command will have the tunable change only take effect after a reboot.
In Example 6-68 we are changing the value of the tcp_recvspace to 16k which is the default but we only want changes to take effect after the reboot.
Example 6-68 The no -r -o tcp_recvspace
[p630n04][/etc/tunables]> no -r -o tcp_recvspace=16k
Setting tcp_recvspace to 16k in nextboot file
Warning: changes will take effect only at next reboot
[p630n04][/etc/tunables]>
As explained earlier, the /etc/tunables/nextboot file is used to set values after a reboot (see Example 6-69).
Example 6-69 Contents of the /etc/tunables/nextboot file
[p630n04][/etc/tunables]> more /etc/tunables/nextboot
# IBM_PROLOG_BEGIN_TAG
# This is an automatically generated prolog. #
# bos530 src/bos/usr/sbin/perf/tune/nextboot 1.1
#
# Licensed Materials - Property of IBM
#
# (C) COPYRIGHT International Business Machines Corp. 2002
# All Rights Reserved
#
# US Government Users Restricted Rights - Use, duplication or
# disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
#
# IBM_PROLOG_END_TAG
vmo:
no:
tcp_recvspace = "16k"
[p630n04][/etc/tunables]>
The vmo, schedo, ioo, no and nfso commands all make use of this file to store their tunable values that will be set at next reboot.
After we executed the no -r -o tcp_recvspace command an entry gets made in the /etc/tunables/nextboot file. In Example 6-69 you will notice that the tcp_recvspace value is set to 16k this will be set when the system is rebooted.
Also if you query the current value of the tcp_recvspace tunable you will note that the tunable value has not changed. See Example 6-70.
Example 6-70 The no -o tcp_recvspace to display the current value
[p630n04][/etc/tunables]> no -o tcp_recvspace
tcp_recvspace = 32768
[p630n04][/etc/tunables]>
To have no tunable values take effect immediately and after a reboot use the no -p command. See Example 6-71. This will have the current no tunable change to the specified value as well as an entry be made in the /etc/tunables/nextboot file.
Example 6-71 The no -p -o tcp_recvspace command
[p630n04][/etc/tunables]> no -p -o tcp_recvspace=16k
Setting tcp_recvspace to 16k
Setting tcp_recvspace to 16k in nextboot file
Change to tunable tcp_recvspace, will only be effective for future connections
[p630n04][/etc/tunables]>
If you want to change the value of a tunable to its default value make use of the no -d command to change a specific value.
In Example 6-72 we are using the no -d command to change the value of the tcp_recvspace tunable to its default value which is 16384 bytes.
Example 6-72 The no -d tcp_recvspace command
[p630n04][/]> no -d tcp_recvspace
Setting tcp_recvspace to 16384
[p630n04][/]>
|
Note: If you use the no -d command to chance a tunable to its default value, the /etc/tunables/nextboot file is not updated. Use the no -p -d combination to have a command set to its default and update the next reboot value. |
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