afc60d017b
This avoids putting a large disk image in the store (and possibly in a binary cache), while improving runtime performance. Assuming you're running an SSD, and/or with plenty of cache (?) it is feasible to preempt the virtualization overhead before VM start, in single-digit seconds. For some tests that perform many reads on the store, the improved performance of EROFS is sufficient that not only the image creation overhead is compensated for, but is actually faster. Stats for nixosTests.gitlab: Baseline without useNixStoreImage: >1000s Baseline with useNixStoreImage without writableStore = false ext4 image in store: 277 seconds + significant image build time and/or disk space Disposable erofs image: 249 seconds _including_ image build time Custom erofs overlay on 9p host store: 391 seconds; presumably because the overlay still performs too many 9p accesses, or perhaps some other overhead. This solution had no obvious performance advantage, while requiring extra options to work, so it was discarded. |
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| .. | ||
| config | ||
| hardware | ||
| i18n/input-method | ||
| installer | ||
| misc | ||
| profiles | ||
| programs | ||
| security | ||
| services | ||
| system | ||
| tasks | ||
| testing | ||
| virtualisation | ||
| module-list.nix | ||
| rename.nix | ||