每天多一点

4 Jan, 2024
流水账
2号加班到比较晚，3号是周三，过了10点半才起来，看到前老板半小时前的消息，尴尬。

专门开车去black sheep 喝了杯手冲，68，还不错。但周边停车太贵了。

然后找管吃了饭，接着去滑板，然后又夜宵。
3 Jan, 2024
Lvm Dm Io Utils
磁盘做 LVM，12块盘做一个LVM ，Strip12。压测（fio 随机读写）的时候，LVM（dm-2) utils 打到100%，但磁盘的才50%不到。导致吞吐量不能更高。

怎么可以突破这个瓶颈呢？
3 Jan, 2024
处女座
我在咖啡店，听到一个顾客的店员的对话。

店里是没有卫生间吗？

对，在旁边，暖光商场里面。

多远？

看你走多快。

NONONO，多远并不取决于走多快~
2 Jan, 2024
流水账
前天看 B 站的跨年演唱会，觉得还不错，今天买入一些 B 站。

今天一上班就搞了两个故障，一个把 FWS SIN 的机器重启后起不来了，可能是 FSTAB 配置有问题，另外一个是更新 Hickwall Kafka 集群配置后，operator 直接重启了 POD，导致一天都在做数据复制。
25 Dec, 2023
Disk Automatically Unmounts Immediately After Mounting
https://www.bentasker.co.uk/posts/documentation/linux/480-disk-automatically-unmounts-immediately-after-mounting.html

When it happens, it’s incredibly frustrating - you’ve had a disk replaced on a linux box, the disk has shown up with a different name in /dev, so you edit /etc/fstab and then try to mount the disk.

The command runs, without error, but the disk isn’t mounted, and doesn’t appear in df

This documentation details the likely cause, and how to resolve it

If you look in dmesg, you might see something like the following
```
[  462.754500] XFS (sdc): Mounting V5 Filesystem
[  462.857216] XFS (sdc): Ending clean mount
[  462.871119] XFS (sdc): Unmounting Filesystem
```
Which, whilst it shows the disk is getting unmounted almost immediately, isn’t otherwise very helpful. It doesn’t tell us why.

However, if you look in syslog (e.g. /var/log/messages, journalctl or /var/log/syslog) you may well see this logged again with a couple of additional relevant lines
```
kernel: XFS (sde): Mounting V5 Filesystem
kernel: XFS (sde): Ending clean mount
systemd: Unit cache2.mount is bound to inactive unit dev-sdc.device. Stopping, too.
systemd: Unmounting /cache2...
kernel: XFS (sde): Unmounting Filesystem
systemd: Unmounted /cache2.
```
We can now see that the erstwhile init system - systemd - decided to unmount the filesystem

systemd: Unit cache2.mount is bound to inactive unit dev-sdc.device. Stopping, too. The reason for this is that at boot time systemd-fstab-generator generates, in effect, a bunch of dynamic unit files for each mount. From the output above we can tell the disk used to be sdc but is now sde. Despite fstab saying
```
/dev/sde      /mnt/cache2   xfs   defaults,nofail  0 0
```
When we issue the command
```
mount /cache2
```
SystemD picks up on the fact that it has an inactive unit file (inactive because the block device has gone away) which should be mounted to that path, decides there’s a conflict, and that it knows better, and unmounts your mount again If you’re in this position, then, you should be able to briefly resolve with a single command
```
systemctl daemon-reload
```
Keep in mind that if your disk moves back following a reboot, you’ll be back to this point where SystemD decides you can’t have wanted to mount your disk after all.

SystemD have a bug for this, raised in 2015 and seemingly still unresolved (it’s certainly still attracting complaints at time of writing). Rather worryingly, it suggests that the above will not always resolve the issue, and instead suggests the following “workaround”
20 Dec, 2023
Linux Shell Variable Render
```
a='a' echo "$a"` 和 `a='a' ; echo "$a"` 有什么区别？
```
我现在的理解是，shell 渲染这个 $a 的时机（顺序）问题，如果没有分号，$a 先渲染，然后才执行命令，foo=bar 是命令的一部分。

shell 会在执行当前命令 之前把 $XX 这种先渲染掉（如果是单引号里面就不渲染了）

加了分号或者是使用 && ，就是两个使用，后面命令执行的时候，变量已经被赋值了。如果没有分号或者没有&&，a=’a’ 是命令的一部分，bash 渲染变量在执行命令之前，所以渲染的时候还没有值。

另外多说一下，在 echo 命令执行的时候，$a 其实是有值的，只不过 echo 跟的参数是 ““，而不是 env(a)。
20 Dec, 2023
Org.xerial.snappy.snappy
java.lang.NoClassDefFoundError: Could not initialize class org.xerial.snappy.Snappy

可能是因为 /tmp 挂载点掉了?

4 Dec, 2023

Resize Fs

lsblk
fdisk /dev/nvme0n1
partprobe
pvcreate /dev/nvme0n1p4
vgextend VolGroup00 /dev/nvme0n1p4
lvdisplay
lvextend -l +100%FREE /dev/VolGroup00/lv_root
lvs
resize2fs /dev/VolGroup00/lv_root
df -h

28 Nov, 2023
Tanyan
跟烦的人打交道的时候，就想着赶紧把他的事处理掉拉倒，反而让对方占便宜了，操，这是一个矛盾。
28 Nov, 2023
Respect
人的相处，我觉得最重要是尊重。

不过每个人对尊重的理解不一样吧，不强求。礼尚往来吧。