Blog: add ramdisk guide

src/content/blog/use-a-ramdisk.md

@@ -0,0 +1,109 @@
+---
+title: 'Use a Ramdisk'
+description: 'Why you should use ramdisks'
+pubDate: 'Dec 29 2023'
+heroImage: '/blog-placeholder-5.jpg'
+---
+
+# RAM Disks
+
+Traditionally, storage is placed on an SSD or HDD, both of which are are types
+of non-volatile storage. This means if your computer loses power or restarts,
+the data will persist on the disk. In most cases, this is desired.
+
+A RAM disk is a type of storage recorded in in RAM. The key difference is that
+RAM is volatile storage.
+
+Let's consider the pros and cons of using RAM for storage:
+
+Pros:
+ - Very fast, faster than the best NVMe drives
+ - True uniform access
+
+Cons:
+ - Limited to the size of your RAM, typically smaller than an SSD or HDD
+ - All data is lost on powerless and reboot
+
+In short, if you have RAM to spare and aren't worried about losing power, a RAM
+disk is far more performant. It's especially noticeable when you're doing a huge
+amount of small reads/writes. In fact, the Chromium project [recommends using a
+RAM disk](https://chromium.googlesource.com/chromium/src/+/main/docs/linux/build_instructions.md#using-tmpfs)
+to build the browser.
+
+## Downloads Folder in RAM
+
+Aside from the speedup, I personally use the RAM disk for its psychological
+benefits. Knowing the storage is volatile motivates me to clean it up.
+
+One example is when making changes to a git repository, I'll often clone the
+repository onto a RAM disk. This reminds me to make *very* frequent commits,
+since I'm constantly a bit concerned my work will be wiped via power outage or
+crash. But the outcome is good atomic-committing in git.
+
+I also put my Downloads folder in the RAM. For one thing, partial downloads from
+Chromium and Firefox don't matter, since neither can pick up where they left
+off. This you'll have to restart an interrupted download even if you are using
+non-volatile storage. I've also found my Downloads folder gets really messy if I
+don't do this. Wiping it on reboot reminds me to move files into their proper
+folders.
+
+The following command will symlink your Downloads folder to the RAM disk. Most
+programs will never notice the difference:
+
+```bash
+rmdir ~/Downloads
+ln -s /dev/shm/ ~/Downloads
+```
+
+## Setting Up a RAM Disk
+
+### Shared Memory
+
+If you're on Linux, you already have a RAM disk! The path `/dev/shm` is found on
+all Linux system. It stands for "shared memory" and is indented as a space for
+users and programs to "share" data. Very few programs and users actually do
+this, but it means that directory is accessible for writing for all users
+including you.
+
+To verify a directory is mounted on a RAM disk, use the following command:
+
+```bash
+df -h .
+# OR if you know the path
+df -h /dev/shm
+```
+
+We care about what the `Filesystem` columns reports. It should be "tmpfs",
+mains "temporary file system". For example mine looks like:
+
+```
+Filesystem      Size  Used Avail Use% Mounted on
+tmpfs            16G  4.0G   12G  26% /dev/shm
+```
+
+We can also see the size of the RAM disk. In this case it's 16GB. By default,
+Linux mounts half the system RAM for `/dev/shm`. This memory is only used if the
+system needs to use it, so initially it takes up 0GB. The "size" is the maximum
+amount of memory the file system can take up.
+
+### Mount a RAM Disk
+
+The particularly adventurous can also mount their own RAM disk. The `mount`
+command bundled with Linux can do this. You will need root privileges.
+
+The following mounts a 1GB RAM disk onto the directory `/home/emiliko/mnt`:
+
+```bash
+sudo mount -t tmpfs -o uid=1000,size=1g tmpfs /home/emiliko/mnt
+```
+
+## Advanced Notes
+
+While in this article I implied all temporary file systems are RAM disks and
+vise versa, neither is technically true. It's possible to run `tmpfs` on
+non-volatile storage, and many servers choose to do this. Similarly, a RAM disk
+can be used for a normal file system, like btrfs.
+
+However, for personal use, you'll never want to disconnect the terms `tmpfs` and
+RAM disk. Using one without the other doesn't make any sense on a personal
+computer and is unusual on a shared computer too.

src/content/unix/ssh.md

@@ -2,6 +2,7 @@
 title: 'SSH Quick Start Guide'
 description: 'The fastest way to get all the SSH essentials out of the way'
 updateDate: 'December 26 2023'
+heroImage: '/ssh-logo.png'
 ---
 
 # SSH

src/content/unix/systemd-timers.md

@@ -1,8 +1,8 @@
 ---
 title: 'Systemd Timers'
 description: "Replacing Crontabs with Systemd's timer mechanism"
-pubDate: 'Dec 25 2023'
+updateDate: 'Dec 29 2023'
-heroImage: '/blog-placeholder-2.jpg'
+heroImage: '/systemd-dark.webp'
 ---
 
 # Systemd Timers