High TCP segment retransmit rate


 
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Operating Systems Linux High TCP segment retransmit rate
# 1  
Old 02-27-2012
High TCP segment retransmit rate

Hi All,

we have some 20 CentOS hosts which are experiencing high TCP segment retrasmit rate. I checked with network team if it is something to do with switch, they say there is no latency or errors.
This is a issue now because the sybase quiries from the DB instances on this host are getting slower.
Can any one let me know how to reduce this TCP segment retransmit rate?

Thanks,
RK
# 2  
Old 02-27-2012
Quote:
Originally Posted by digitalrg
we have some 20 CentOS hosts which are experiencing high TCP segment retrasmit rate.
This is a issue now because the sybase quiries from the DB instances on this host are getting slower.
Can any one let me know how to reduce this TCP segment retransmit rate?
there are some kernel options for ipv4 & ipv6 to set 'retrans_time'.
don't know if it works setting it to a higher value...
# 3  
Old 02-28-2012
Hi daWonderer,

Changed this to 200 from 99 and restarted eth, but still didnt work.
Any other pointers please?

Thanks,
RK
# 4  
Old 02-28-2012
Check the value to see if you get back out what you put into it.

I don't think you'd need to restart eth for this. That might even undo your changes.
# 5  
Old 02-28-2012
Hi Corona,

Still no go...... Smilie
Interestingly I found that this increases over a period of 4 hours 12:00 to 16:00 EST. I happen to see if any switch issues - no. any db/application traffic increase-no

So any one needs more info to dig through?

-RK
# 6  
Old 02-28-2012
Quote:
Originally Posted by digitalrg
Hi Corona,

Still no go...... Smilie
Did you get the same value out of it that you put into it?
# 7  
Old 02-29-2012
Yes I reverted the value back to 99. and still not working.
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