Description

This week Steve gives us a deep dive into performance tuning, and we talk about how your body's memory functions.

-- During The Show --

00:50 Intro

• Subsisting greeting variables
• Accessible memory
• Strength of memory
• Reading and writing builds "Accessible memory"
• Teaching builds "Strength of memory"
• Go look up "space repetition"
• Reader come home book
• YouTube if you check their sources

17:55 News Wire

• OpenSSL Security Update - github.com

• Git 2.56 - github.blog

• Thunderbird 157 - thunderbird.net

• Firefox 157 firefox.com - firefox.com

• Shotcut 26.9 - phoronix.com

• Tails 7.14 - torproject.org

• Parrot OS 7.4 - parrotsec.org

• OpenMandriva ROME 26.09 - openmandriva.org

• Nitrux 7.0 - opensourcefeed.org

• Antix 26.1 - antixlinux.com

• SMTP Backdoors - infosecurity-magazine.com

• COSMIC Desktop No Longer Accepts AI Content - reddit.com

• Beam AI - fortune.com

• Google Halts Open Source Bug Bounty Program - bleepingcomputer.com

19:15 Performance Tuning

• Defaults are someone guessing at a "safe option"
• Three hosts being tuned
  • NAS (file server)
  • vHost (virtual disks live here)
  • Container Host
• When should you performance tune?
  • Broadcasting
  • Networks (ISPs)
• The more "dense" the more benefits
• TuneD
• ZFS "Adaptive Replacement Cache" (ARC)
  • Default is 50% of RAM
• Swap file
  • System doesn't empty on its own
• ARC stats
  • Hits and misses
  • Resets on reboot
• Memory pressure
• Swapyness
  • 60 is the default
  • the "cliff rate"
  • Tuned to around 10%-30% on "performance profiles"
  • System starts swapping before you hit zero RAM
• ZFS record size
  • Record size is the "Maximum" not "Fixed size"
  • Media Library 1M
  • Postgres 16K
  • ZFS write amplification (8k writes to 1M records hurt)
• AI study bot rules
• Man systemd.directives
• Write in and tell us if you want more!

Extra Credit: What to search after the show

• ZFS ARC Tuning
• ZFS Record Size
  • ZFS send receive preserves record size
  • Record size is per "data set" not directory
  • Record size only affects new writes
  • "zfs_dirty_data_max" vs "vm.dirty_ratio"
  • "QEMU "cache=none" O_DIRECT"
  • Postgres on NFS PGDATA caveats
• "Tuned-adm virtual-host" hypervisor profile (The one nobody mentions)
• Tuned profile format "sysctl" vs "main" the plugin/argument split
• NFS mount options (the client side fix)
• "vmstat" reading swap columns correctly

-- The Extra Credit Section --

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