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errpt -a reveals LOW_MBUFS.....
- Thread starter monman
- Start date
Mon,
This sounds like MBUF problems - check 'netstat -an' for MBUFS being denied. If this is the case follow the advice below.
To increase the number of MBUFS you need to increase the value of the wall. This is effectively the max. amount of memory allocated to networking.
Check the current setting via:
no -o thewall
Change via:
no -o thewall=<new value>
The current value depends on the AIX level i.e. the proportion of memory allocated by default differs between 4.1, 4.2 and 4.3. Typically it tends to be about half of memory in AIX 4.3.3 (if I am remembering correctly, I do not have a machine to check).
I would see what is currently set to in relation to the size of memory and then increase this by some linked value to memory size i.e. 1/4 of memory to 1/3 memory. Then check via : 'netstat -an' for MBUF's denied messages after the increase.
It is also important to note that if you just change the setting via the no command it will only be effective until the next reboot, to make a peramant also add the command to /etc/rc.net on non-SP boxes and to tuning.cust if they are SP's.
Best of Luck PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP
This sounds like MBUF problems - check 'netstat -an' for MBUFS being denied. If this is the case follow the advice below.
To increase the number of MBUFS you need to increase the value of the wall. This is effectively the max. amount of memory allocated to networking.
Check the current setting via:
no -o thewall
Change via:
no -o thewall=<new value>
The current value depends on the AIX level i.e. the proportion of memory allocated by default differs between 4.1, 4.2 and 4.3. Typically it tends to be about half of memory in AIX 4.3.3 (if I am remembering correctly, I do not have a machine to check).
I would see what is currently set to in relation to the size of memory and then increase this by some linked value to memory size i.e. 1/4 of memory to 1/3 memory. Then check via : 'netstat -an' for MBUF's denied messages after the increase.
It is also important to note that if you just change the setting via the no command it will only be effective until the next reboot, to make a peramant also add the command to /etc/rc.net on non-SP boxes and to tuning.cust if they are SP's.
Best of Luck PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP
- Thread starter
- #3
PSD,
onwall=2048 (2K!) I reset this to 65536 then ran my FTP test again which whizzed through..thankyou.
Unfortunately though, although the testing people noticed a difference after I did this, they now say that it has gone slow again. I've run top,iostat, checked processes, even errpt to check that the MBUF mssge isn't re-occuring but cannot find anything wrong. onwall is still set to 65536.
netstat -nr is not reporting anything either.
I have not though, looking at your note again, rebooted the box. Are you sure this is necessary.
Regards,
Mon
onwall=2048 (2K!) I reset this to 65536 then ran my FTP test again which whizzed through..thankyou.
Unfortunately though, although the testing people noticed a difference after I did this, they now say that it has gone slow again. I've run top,iostat, checked processes, even errpt to check that the MBUF mssge isn't re-occuring but cannot find anything wrong. onwall is still set to 65536.
netstat -nr is not reporting anything either.
I have not though, looking at your note again, rebooted the box. Are you sure this is necessary.
Regards,
Mon
- Thread starter
- #4
Momman,
Typically you may have other tcp/ip "no" settings near the very bottom of the file, if you do not append the line to the bottom.
My previous mail did not say you needed to reboot the box, only that if you did you would lose the new wall setting. You do not need to reboot as this setting can be changed dynamically.
I suspect that if the network test speeded up then slowed back down again that you have a speed issue on your network i.e. a network problem. Also check the output of entstat en0 (or whatever you primary card is) and look for dropped packets indicating speed/duplex issues between the card and the switch.
Best of luck
PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP
Typically you may have other tcp/ip "no" settings near the very bottom of the file, if you do not append the line to the bottom.
My previous mail did not say you needed to reboot the box, only that if you did you would lose the new wall setting. You do not need to reboot as this setting can be changed dynamically.
I suspect that if the network test speeded up then slowed back down again that you have a speed issue on your network i.e. a network problem. Also check the output of entstat en0 (or whatever you primary card is) and look for dropped packets indicating speed/duplex issues between the card and the switch.
Best of luck
PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP
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