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backup/verify: improve speed by sorting chunks by inode

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before reading the chunks from disk in the order of the index file,
stat them first and sort them by inode number.

this can have a very positive impact on read speed on spinning disks,
even with the additional stat'ing of the chunks.

memory footprint should be tolerable, for 1_000_000 chunks
we need about ~16MiB of memory (Vec of 64bit position + 64bit inode)
(assuming 4MiB Chunks, such an index would reference 4TiB of data)

two small benchmarks (single spinner, ext4) here showed an improvement from
~430 seconds to ~330 seconds for a 32GiB fixed index
and from
~160 seconds to ~120 seconds for a 10GiB dynamic index

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
This commit is contained in:
Dominik Csapak 2021-04-13 16:35:36 +02:00 committed by Thomas Lamprecht
parent 7afb98a912
commit 7f394c807b
2 changed files with 34 additions and 3 deletions
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5
src/backup/datastore.rs
View File

@ -686,6 +686,11 @@ impl DataStore {
}
pub fn stat_chunk(&self, digest: &[u8; 32]) -> Result<std::fs::Metadata, Error> {
let (chunk_path, _digest_str) = self.chunk_store.chunk_path(digest);
std::fs::metadata(chunk_path).map_err(Error::from)
}
pub fn load_chunk(&self, digest: &[u8; 32]) -> Result<DataBlob, Error> {
let (chunk_path, digest_str) = self.chunk_store.chunk_path(digest);

32
src/backup/verify.rs
View File

@ -159,13 +159,16 @@ fn verify_index_chunks(
}
);
for pos in 0..index.index_count() {
let index_count = index.index_count();
let mut chunk_list = Vec::with_capacity(index_count);
use std::os::unix::fs::MetadataExt;
for pos in 0..index_count {
verify_worker.worker.check_abort()?;
crate::tools::fail_on_shutdown()?;
let info = index.chunk_info(pos).unwrap();
let size = info.size();
if verify_worker.verified_chunks.lock().unwrap().contains(&info.digest) {
continue; // already verified
@ -178,15 +181,38 @@ fn verify_index_chunks(
continue;
}
match verify_worker.datastore.stat_chunk(&info.digest) {
Err(err) => {
verify_worker.corrupt_chunks.lock().unwrap().insert(info.digest);
task_log!(verify_worker.worker, "can't verify chunk, stat failed - {}", err);
errors.fetch_add(1, Ordering::SeqCst);
rename_corrupted_chunk(verify_worker.datastore.clone(), &info.digest, &verify_worker.worker);
}
Ok(metadata) => {
chunk_list.push((pos, metadata.ino()));
}
}
}
chunk_list.sort_unstable_by(|(_, ino_a), (_, ino_b)| {
ino_a.cmp(&ino_b)
});
for (pos, _) in chunk_list {
verify_worker.worker.check_abort()?;
crate::tools::fail_on_shutdown()?;
let info = index.chunk_info(pos).unwrap();
match verify_worker.datastore.load_chunk(&info.digest) {
Err(err) => {
verify_worker.corrupt_chunks.lock().unwrap().insert(info.digest);
task_log!(verify_worker.worker, "can't verify chunk, load failed - {}", err);
errors.fetch_add(1, Ordering::SeqCst);
rename_corrupted_chunk(verify_worker.datastore.clone(), &info.digest, &verify_worker.worker);
continue;
}
Ok(chunk) => {
let size = info.size();
read_bytes += chunk.raw_size();
decoder_pool.send((chunk, info.digest, size))?;
decoded_bytes += size;