ZFS VDEV Types and ARC Interactions, New LXC Containers for TrueNAS 26 | TrueNAS Tech Talk (T3) E050

On today's TrueNAS Tech Talk, it's another round of technical information. Chris goes into the details on some of the additional VDEV types and how they interact with the ZFS Adaptive Replacement Cache (ARC) - should you make room for an extra SSD or two in your system? Kris also reveals the upcoming changes to the LXC Container ecosystem in TrueNAS 26 - now merged in the nightlies and ready for testing. Check out our main channel at ‪@TrueNAS‬ Submit questions to [email protected] Download TrueNAS for yourself: https://www.truenas.com/truenas-commu... Check out TrueNAS Enterprise appliances: https://www.truenas.com/truenas-enter... Visit the TrueNAS Community Forums: https://forums.truenas.com/ Listen to T3 on Spotify: https://open.spotify.com/show/50CEMeS... Chapters 00:00 Intro 00:26 More Technical Information Upcoming 01:26 Adaptive Replacement Cache (ARC) - The "Tier One" Cache 03:27 MRU and MFU - Two Algorithms for the Price of One 04:27 Ghost Write the List - When ZFS "Missed it by That Much" 05:59 The arc_summary script - Demand, Prefetch, Data, Metadata 07:00 Adaptive Prefetching and Simultaneous Sequential Reads 08:28 More than just Size - RAM speed starts to matter at 40Gbps 09:42 Redundancy is for Data, Not Cache - When to Bypass ARC 11:13 Flip the Script with Compressed ARC - Disable Client Cache? 11:40 Use the TrueNAS Defaults as your Baseline - Measure Impact 12:19 L2ARC - Supplemental Cache, Not as Adaptive 12:49 L2ARC Feeds from the Tail End of ARC - FIFO Ring Buffer 13:35 Reads from L2ARC get Promoted Back to ARC 14:03 Why does L2ARC fill so slowly? Defaults preserve endurance 15:52 If ARC and L2ARC hold metadata, why have a Special VDEV? 18:36 SLOG devices (still aren't cache) - it's a copy of dirty data 19:13 Your SLOG is your bottleneck for sync write speed 20:00 Aside: Is SLOG worth it on all-flash VDEVs? Sometimes. (Test!) 21:40 TrueNAS 26 - LXC Containers are Libvirt Based 22:19 No More "Experimental" Label - Apps, Containers, VMs 23:16 GPU and USB Device Passthrough for Containers 24:22 Call for Testing - Weird USB Devices (TV Tuners, Coral TPU) 26:00 Automated Migration from 25.10 (but check passthrough) 26:54 Disable Container AutoStart if you're Experimenting 27:27 Quick Note on TrueNAS WebShare - BYO SSL Certs are Fine 28:40 Thank you for Tuning In!