2014年4月11日 星期五

No Dropbox icon in Ubuntu 13.10

1. Install package
# sudo apt-get install libappindicator1
2.  Log out, and then log back in (or issue dropbox stop && dropbox start at the command line)

REF

Linux Kernel Performance Tuning and Hardening

[Security]Deactivates automatic answers to ICMP broadcasts and protects against smurf attacks.
net.ipv4.icmp_echo_ignore_broadcasts=1
[Security]Enable source validation by reversed path, as specified in RFC1812
/*
0 - No source validation.
1 - Strict mode as defined in RFC3704 Strict Reverse Path. 
    Each incoming packet is tested against the FIB and if the interface
    is not the best reverse path the packet check will fail. 
    By default failed packets are discarded.
2 - Loose mode as defined in RFC3704 Loose Reverse Path. 
    Each incoming packet's source address is also tested against the FIB
    and if the source address is not reachable via any interface the packet check will fail.
*/
net.ipv4.conf.all.rp_filter = 1
[Performance]The number of possible inotify(7) watches
fs.inotify.max_user_watches = 65536
[Tuning]Avoid deleting secondary IPs on deleting the primary IP.
/*
If you remove the primary IP address, all secondary addresses are purged by default as well. 
*/
net.ipv4.conf.default.promote_secondaries = 1
net.ipv4.conf.all.promote_secondaries = 1"
[Security]Not allow source route
net.ipv4.conf.default.accept_source_route = 0
[Tuning]Disable listen for router advertisements in order to choose an IPV6 address and router
net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.all.accept_ra = 0
[Security]Do not allow redirect
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
[Tuning]Avoid tcp timeout
net.ipv4.tcp_timestamps = 0
[Performance]Maximum amount for the receive socket memory
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.ipv4.tcp_rmem = 32768 262144 33554432
net.ipv4.tcp_wmem = 32768 262144 33554432
[Performance]Max open file
fs.file-max = 200000
[Performance]The number of IPC message queue resources allowed
kernel.msgmni = 1024
[Performance]How many semaphore arrays, semaphores can be allocate and how many semaphores can be in a single semaphore array
kernel.sem = 400 307200 128 1024
[Performance]Keepalive time
net.ipv4.tcp_keepalive_time = 900
net.ipv4.tcp_keepalive_probes = 5
net.ipv4.tcp_keepalive_intvl = 10
[Performance] Page cache limit.
/*Some app use large amounts of memory for accelerated access to business data
Parts of this memory are seldom accessed. When a user request then needs to
access paged out memory, the response time is poor. It is even worse, when an
SAP solution running on Java incurs a Java garbage collection. The system
starts heavy page-in (disc I/O) activity and has a poor response time for an
extended period of time.*/
vm.pagecache_limit_mb = 41000
Max number of open file
* hard nofile 32768
* soft nofile 32768