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revised FreeBSD performance tuning: Sysctl parameter, loader.conf, kernel
deleted 3 characters in body
Jan
24
comment How to reliably capture Linux kernel log messages in case of a system debilitating crash (BUG, panic)?
try pstore: kernel.org/doc/Documentation/ABI/testing/pstore
Jan
6
comment After Upgrading to Ubuntu 15.10 from 15.04, EC2 Webservers are Crashing
You can either use netconsole or crashdump (RHEL: access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/…;, Ubuntu: help.ubuntu.com/lts/serverguide/kernel-crash-dump.html). On physical machines you could also use pstore driver for that. Anyway. Even after you capture dmesg you'll end up upgrading/downgrading kernel as a simplest solution so be prepared for that. Unless you have a person on your team who can fix/workaround GPE in your current kernel.
Dec
31
comment Linux memory fragmentation
"only if it thinks they are beneficial" - that adds additional heuristic and make system less predictable. Also page replacement algorithms(used in swap and anonymous mmap) are implemented differently on different kernels (e.g. Linux vs FreeBSD), or even different versions of the same OS (2.6.32 vs 3.2 vs 3.10).. "it permits modified pages [...] to be ejected from [...] physical memory" - that will hide memory leaks. "handle cases where much more memory is reserved than is used" - slow system is way worse than down system, so "sane" is questionable.
Dec
31
comment Linux memory fragmentation
Because there is not enough information in the original post, maybe process is just leaking and start swapping. Also i do not see any legitimate reasons for using swap on pretty much any production system (m.b. only for shared workstations for students).
Dec
30
answered Linux memory fragmentation
Dec
1
revised Will increasing net.core.somaxconn make a difference?
deleted 36 characters in body
Oct
15
awarded  Enlightened
Oct
15
awarded  Nice Answer
Sep
3
comment Linux: Why does the CPU frequency fluctuate when using the performance governor?
1) not sure. need to consult with Intel Architectures Software Developer's Manual. 2) yes. PS. You may also want to play with x86_energy_perf_policy
Sep
1
answered Linux: Why does the CPU frequency fluctuate when using the performance governor?
Jul
24
comment Effects of IW10 (initcwnd 10 initrwnd 10) on high speed LAN based TCP/IP communications?
IW10 can also increase retransmit rates due to it's more "bursty" behaviour. Google measured that increase being around 0.5%.
Jul
24
awarded  Disciplined
Jul
22
reviewed Approve How to securely join two networks together over the Internet?
Jul
22
reviewed Approve How to securely join two networks together over the Internet?
Jul
22
reviewed Approve How to securely join two networks together over the Internet?
Jul
21
answered centos doesn't reply to icmp request
Jun
25
reviewed Approve Cannot access network shares by hostname over SSL VPN
Jun
25
reviewed Approve PHP/FastCgi - Which is the threshold over which to use nginx instead of apache
Jun
25
reviewed Approve IPv6 users see different site than IPv4 users