Performance tuning of zfs infrastructure

Our zfs deployment currently only uses rotative storage.

This is (very) suboptimal, and we get noticeable load issues and poor performance, for instance when doing I/O intensive tasks on the annex (the most glaring one being the nfs server becoming slow/unresponsive, which triggers icinga alerts on the reverse proxy).

This task will survey the current best practices for using faster storage in the performance-sensitive parts of ZFS (SLOG, L2ARC, ...) and come up with a few quotes to implement them.

Candidates for actual faster storage:

• Intel Optane storage
• PCIe NVMe storage
• PCIe M.2 adapter + M.2 NVMe disks
• SAS SSDs

References

About ZFS in general

• http://cuddletech.com/?s=zfs&button=Search

About the ZFS Intent Log (ZIL), Separate/Secondary Intent Log (SLOG), and zfs sync flags

• https://jrs-s.net/2019/05/02/zfs-sync-async-zil-slog/
• https://www.ixsystems.com/blog/zfs-zil-and-slog-demystified/
• https://www.ixsystems.com/blog/o-slog-not-slog-best-configure-zfs-intent-log/
• https://www.reddit.com/r/zfs/comments/atiolf/zfs_nvme_slog_syncalways/eh1c9p2/

About SSDs with power loss protection

• https://www.ixsystems.com/community/threads/list-of-ssds-with-power-loss-protection.63998/

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Migrated from T1958 (view on Phabricator)