CODEWITHSUNDEEP
algorithmbashrsyncmirroringrsh
devsda
devsda

Reputation: 4222

Determine the delay in mirroring ( mirroring is done by using rsync and rsh )

I have a master server, that crawls data on web, and do indexing. And after that it starts mirroring to all the mirror server.

For that I use rsync and rsh.

But before start updating in mirror server, it takes time. I want to find where that delay occurs.

My understanding

It might be takes time in reverse DNS Lookup.

My questions

EDITED

  1. Is it right to add some log in rsh.c code or in rsync code
  2. If first question's answer is yes, then I want to make a list of time consumed when Reverse DNS Lookup is enabled and when Reverse DNS Lookup is disabled, so tell me what can do for that?

Tell me where can I add log to note the time consumed?

If my understanding and questions are not upto mark or relevant according to the task that I want, then please correct me, and give me better path, so that I can achieve my goal.

Thanks in advance. Looking for your kind response.

Edit No. 2

Basically I am analyzing the time consumed to determine the delay reason. Nothing to modufy the existing code.

My task is to analyze the code , and find the reason of delay. Thats it.

I think now all the things of my task is clear to you.

Upvotes: 0

Views: 172

Answers (1)

Sorin
Sorin

Reputation: 5395

Before changing rsh, you may try using strace to see which system calls take longer.

strace -c will produce a list of system calls and % of time used by those calls. (should help with the second question also)

For the DNS look-up to be evident you can use ltrace:

example:

ltrace -c -o log.txt wget http://dkjflsdfjka/

Then log.txt will have something like:

root@host:~# head log.txt 
% time seconds usecs/call calls function 
------ ----------- ----------- --------- -------------------- 
74.27 0.130779 130779 1 getaddrinfo 
6.63 0.011680 33 344 strlen 
3.05 0.005371 35 152 free 
2.98 0.005255 35 147 malloc 
2.74 0.004830 38 127 fgets

then you can see ... the getaddrinfo call is taking most of the time

Upvotes: 1

Related Questions