16.
There are a few generic recommendations that should be followed when
trying to optimize system performance. Which of the following is not one
of them?
- A.Do not try out performance optimization on a production server. Using a wrong parameter may crash the server and you do not want that to happen on production.
- B.Use one tool only to analyze system performance data. Using another tool may give different results, which does not help.
- C.Change one setting at a time and verify it’s working.
- D.Make a plan before you start and do not just modify random parameters.
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| It is not a good idea to focus on one tool only while analyzing performance parameters. The tool you are using might be outdated and showing wrong information. So, you better try gathering performance parameters with as many tools as possible (or get the performance information directly from /proc). |
17.
Which file do you need to change to enable packet forwarding between network
cards on your server?
- A./proc/net/router
- B./proc/net/ipv4/ip_forward
- C./proc/sys/net/ipv4/ip_forward
- D./proc/sys/net/ipv4/router
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| The /proc/sys directory contains tunable settings. In this directory, the ipv4/ip_forward file is used to enable packet forwarding. Make sure that this file contains a 1 if you want your server to be able to forward packets between interfaces. |
18.
Where in the /proc file system do you find the settings that can be used to
optimize memory usage?
- A./proc/sys/mem
- B./proc/sys/vm
- C./proc/sys/kern
- D./proc/sys/vfs
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| The /proc/sys/vm directory contains memory tunables. VM in the directory stands for virtual memory. |
19.
Which file would you look at to get detailed information on system memory
usage?
- A./proc/meminfo
- B./proc/memory
- C./proc/iomem
- D./proc/kcore
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| The /proc/meminfo file contains detailed information about current system memory usage. The /proc/memory file does not exist. /proc/ iomem has information specifically about io related memory, and /proc/kcore is the raw memory image that the kernel is using. |
20.
Which parameter would you change to block ping packets while still allowing
other ICMP packets?
- A./proc/sys/net/ipv4/icmp_echo_ignore_all
- B./proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
- C./proc/sys/net/ipv4/icmp_ignore_ping
- D./proc/sys/net/ipv4/tcp_block_icmp_ping
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| Answer A blocks all ICMP packets, not just ping. Answers C and D do not refer to valid filenames in /proc. |
|
|
||||||||||||||||||||||||||||
