调整 net.ipv4.tcp_tw_recycle 造成的故障

  • 背景

在 nat 的网络环境访问服务器时会有不定时连接超时的问题

  • 原因

出现此问题,可能是系统参数设置问题,即以下两个参数都设置为 1

net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tw_recycle = 1

RFC1323中有如下一段描述:

An additional mechanism could be added to the TCP, a per-host cache of the last timestamp received from any connection. This value could then be used in the PAWS mechanism to reject old duplicate segments from earlier incarnations of the connection, if the timestamp clock can be guaranteed to have ticked at least once since the old connection was open. This would require that the TIME-WAIT delay plus the RTT together must be at least one tick of the sender’s timestamp clock. Such an extension is not part of the proposal of this RFC. ...

ProxmoxVE更换ZFS rpool系统盘

之前配置的Proxmox服务器系统盘一律使用ZFS Mirror模式,前段时间SMART提示有个硬盘有坏道了。拿了个新盘替换上去,做个笔记记录一下操作流程。
首先查看一下ZFS池状态:

[email protected]:~# zpool status -v   pool: rpool  state: ONLINE   scan: scrub repaired 0B in 0h41m with 0 errors on Sun Dec  8 01:05:19 2019 config:     NAME        STATE     READ WRITE CKSUM     rpool       ONLINE       0     0     0       mirror-0  ONLINE       0     0     0         sda2    ONLINE       0     0     0         sdb2    ONLINE       0     0     0 errors: No known data errors ...

QUIC.Cloud – LiteSpeed出品的WordPress全站全球缓存解决方案

前言

以目前建站来说,无非是 LAMP 或者 LNMP 架构,这两种架构主要区别在于网页程序解析器是用 Apache 还是 Nginx ,两种程序各有利弊,但是能不能将两个程序的优点综合起来呢? LiteSpeed 就是做到了这么一点,以超高的 Apache 兼容性和 Nginx 并发性,使得 LiteSpeed 在这几年越来越流行,特别是对于 WordPress , LiteSpeed 更是有自己强大的优化,本站目前也是运行 OpenLiteSpeed 上,不得不说,性能确实提升不少。 ...

WordPress 5.0以上版本重置后台密码

近期登录我的一个博客站的时候, 发现记录的备份密码错误, 由于我有定期更新密码的习惯, 想来是上次更新过后没有更新密码记录器里面的数值.  百度了几个教程, 大部分是通过CPANEL 重置PHD ADMIN里面的数值, 以前也一直这样操作. 然而这次操作了两次发现仍然不管用, 不管是把使用MD5编译器, 还是使用其他教程里面提到的方法, 全部失效. ...

ODROID-H2 双网口HTPC

Key Features

  • Intel Quad-core processor J4105 (14nm) with 4MiB Cache, up to 2.5Ghz(Single Thread) or 2.3Ghz(Multi Thread)
  • Dual-channel Memory DDR4-PC19200 (2400MT/s)
  • Total 32GiB RAM Space with two SO-DIMM slots
  • 4 x PCIe 2.0 for one M.2 NVMe storage
  • 2 x Gbit Ethernet ports
  • 2 x SATA 3.0
  • SSE4.2 accelerator (SMM, FPU, NX, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AES)
  • Intel UHD Graphics 600 (Gen9.5 LP GT1) up to 700Mhz
  • HDMI 2.0 and DP 1.2 multiple 4K/60Hz video outputs
  • RTC / BIOS backup battery is included

From June 2019, Rev-B board will be shipped. The improvements are as below; 

– CLK-REQ signal pull resistor is added to support a PCIe-to-SATA bridge board
– 12V SATA power source improvement for high power HDDs.
– Add a M.2 screw for NVMe storage installation
– Preinstalled the latest BIOS 1.05.
– more detail to WiKi https://wiki.odroid.com/odroid-h2/hardware#odroid-h2_schematics
...