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21b3e1d13b
We can currently underflow `pageserver_resident_physical_size_global`, so the used disk bytes would show `u63::MAX` by mistake. The assumption of the API (and the documented behavior) was to give the layer files disk usage. Switch to reporting numbers that match `df` output. Fixes: #7336
51 lines
1.6 KiB
Rust
51 lines
1.6 KiB
Rust
//! An utilization metric which is used to decide on which pageserver to put next tenant.
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//!
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//! The metric is exposed via `GET /v1/utilization`. Refer and maintain it's openapi spec as the
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//! truth.
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use anyhow::Context;
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use std::path::Path;
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use pageserver_api::models::PageserverUtilization;
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pub(crate) fn regenerate(tenants_path: &Path) -> anyhow::Result<PageserverUtilization> {
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// TODO: currently the http api ratelimits this to 1Hz at most, which is probably good enough
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let statvfs = nix::sys::statvfs::statvfs(tenants_path)
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.map_err(std::io::Error::from)
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.context("statvfs tenants directory")?;
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// https://unix.stackexchange.com/a/703650
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let blocksz = if statvfs.fragment_size() > 0 {
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statvfs.fragment_size()
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} else {
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statvfs.block_size()
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};
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#[cfg_attr(not(target_os = "macos"), allow(clippy::unnecessary_cast))]
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let free = statvfs.blocks_available() as u64 * blocksz;
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#[cfg_attr(not(target_os = "macos"), allow(clippy::unnecessary_cast))]
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let used = statvfs
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.blocks()
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// use blocks_free instead of available here to match df in case someone compares
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.saturating_sub(statvfs.blocks_free()) as u64
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* blocksz;
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let captured_at = std::time::SystemTime::now();
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let doc = PageserverUtilization {
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disk_usage_bytes: used,
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free_space_bytes: free,
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// lower is better; start with a constant
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//
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// note that u64::MAX will be output as i64::MAX as u64, but that should not matter
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utilization_score: u64::MAX,
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captured_at,
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};
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// TODO: make utilization_score into a metric
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Ok(doc)
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}
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