check back in cost explorer in February

• sudo yum update
• sudo amazon-linux-extras install -y nginx1 && sudo systemctl enable nginx.service && sudo systemctl start nginx.service start nginx
• aws --region=us-east-1 ec2 describe-spot-price-history --instance-types t4g.micro --start-time=$(date +%s) --product-descriptions="Linux/UNIX" --query 'SpotPriceHistory[*].{az:AvailabilityZone, price:SpotPrice}'
• aws ec2 describe-images --owners amazon --filters "Name=name,Values=al2*" "Name=architecture,Values=arm64" --query 'sort_by(Images, &CreationDate)[-1].ImageId' --output text

• top use shift + m to sort by memory
• free -m
• cat /proc/meminfo
• sudo slabtop

spicy

• echo 2 > /proc/sys/vm/drop_caches requires being sudo
  • this freed 85MB / 20% of memory, could be cron every 12 hours if you want to make Linus unhappy. I noticed after an hour it went back to its regular value of 126M / 34% usage
• echo vm.vfs_cache_pressure=1000 >> /etc/sysctl.conf requires being sudo
• sudo sysctl -w vm.swappiness=10
• sudo sysctl -w vm.vfs_cache_pressure=200

• AL2 Arm t4g.nano has 169MB free, 79MB used / 435MB. (0MB used in swap, if this is high then it needs to be expanded)
• in theory socket.io can handle ~1,000 (200MB) concurrent connections on this machine
• redis should only be used on machines with at least 4GB RAM, t4g medium would cost $7

• .5GB = $1.01 / month
• 1GB = $1.80
• 2GB = $4.03
• 4GB = $7.27