block manager: multi-directory layout computation

This commit is contained in:
Alex 2023-09-05 13:43:38 +02:00
parent 71c0188055
commit 6c420c0880
5 changed files with 256 additions and 30 deletions

1
Cargo.lock generated
View file

@ -1300,6 +1300,7 @@ dependencies = [
"async-compression",
"async-trait",
"bytes",
"bytesize",
"futures",
"futures-util",
"garage_db",

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@ -24,6 +24,7 @@ opentelemetry = "0.17"
arc-swap = "1.5"
async-trait = "0.1.7"
bytes = "1.0"
bytesize = "1.2"
hex = "0.4"
tracing = "0.1"
rand = "0.8"

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@ -4,14 +4,23 @@ use serde::{Deserialize, Serialize};
use garage_util::config::DataDirEnum;
use garage_util::data::Hash;
use garage_util::error::{Error, OkOrMessage};
use garage_util::migrate::*;
pub const DRIVE_NPART: usize = 1024;
type Idx = u16;
const DRIVE_NPART: usize = 1024;
const DPART_BYTES: (usize, usize) = (2, 3);
#[derive(Serialize, Deserialize, Debug, Clone)]
pub(crate) struct DataLayout {
pub(crate) data_dirs: Vec<DataDir>,
pub(crate) partitions: Vec<Partition>,
/// Primary storage location (index in data_dirs) for each partition
pub(crate) part_prim: Vec<Idx>,
/// Secondary storage locations for each partition
pub(crate) part_sec: Vec<Vec<Idx>>,
}
#[derive(Serialize, Deserialize, Debug, Clone)]
@ -20,38 +29,255 @@ pub(crate) struct DataDir {
pub(crate) state: DataDirState,
}
#[derive(Serialize, Deserialize, Debug, Clone)]
#[derive(Serialize, Deserialize, Debug, Clone, Copy)]
pub(crate) enum DataDirState {
Active { capacity: u64 },
ReadOnly,
}
#[derive(Serialize, Deserialize, Debug, Clone)]
pub(crate) struct Partition {
pub(crate) prim: usize,
pub(crate) sec: Vec<usize>,
}
impl DataLayout {
pub(crate) fn initialize(dirs: &DataDirEnum) -> Self {
todo!()
pub(crate) fn initialize(dirs: &DataDirEnum) -> Result<Self, Error> {
let data_dirs = make_data_dirs(dirs)?;
// Split partitions proportionnally to capacity for all drives
// to affect primary storage location
let total_cap = data_dirs.iter().filter_map(|x| x.capacity()).sum::<u64>();
let mut part_prim = Vec::with_capacity(DRIVE_NPART);
let mut cum_cap = 0;
for (i, dd) in data_dirs.iter().enumerate() {
if let DataDirState::Active { capacity } = dd.state {
cum_cap += capacity;
let n_total = (cum_cap * DRIVE_NPART as u64) / total_cap;
part_prim.resize(n_total as usize, i as Idx);
}
}
assert_eq!(cum_cap, total_cap);
assert_eq!(part_prim.len(), DRIVE_NPART);
// If any of the storage locations is non-empty, add it as a secondary
// storage location for all partitions
let mut part_sec = vec![vec![]; DRIVE_NPART];
for (i, dd) in data_dirs.iter().enumerate() {
if dir_not_empty(&dd.path)? {
for (sec, prim) in part_sec.iter_mut().zip(part_prim.iter()) {
if *prim != i as Idx {
sec.push(i as Idx);
}
}
}
}
Ok(Self {
data_dirs,
part_prim,
part_sec,
})
}
pub(crate) fn update(&mut self, dirs: &DataDirEnum) -> Self {
todo!()
pub(crate) fn update(&mut self, dirs: &DataDirEnum) -> Result<Self, Error> {
// Compute list of new data directories and mapping of old indices
// to new indices
let data_dirs = make_data_dirs(dirs)?;
let old2new = self
.data_dirs
.iter()
.map(|x| {
data_dirs
.iter()
.position(|y| y.path == x.path)
.map(|x| x as Idx)
})
.collect::<Vec<_>>();
// Compute secondary location list for partitions based on existing
// folders, translating indices from old to new
let mut part_sec = self
.part_sec
.iter()
.map(|dl| {
dl.iter()
.filter_map(|old| old2new.get(*old as usize).copied().flatten())
.collect::<Vec<_>>()
})
.collect::<Vec<_>>();
// Compute a vector that, for each data dir,
// contains the list of partitions primarily stored on that drive
let mut dir_prim = vec![vec![]; data_dirs.len()];
for (ipart, prim) in self.part_prim.iter().enumerate() {
if let Some(new) = old2new.get(*prim as usize).copied().flatten() {
dir_prim[new as usize].push(ipart);
}
}
// Compute the target number of partitions per data directory
let total_cap = data_dirs.iter().filter_map(|x| x.capacity()).sum::<u64>();
let mut cum_cap = 0;
let mut npart_per_dir = vec![];
for dd in data_dirs.iter() {
if let DataDirState::Active { capacity } = dd.state {
let begin = (cum_cap * DRIVE_NPART as u64) / total_cap;
cum_cap += capacity;
let end = (cum_cap * DRIVE_NPART as u64) / total_cap;
npart_per_dir.push((end - begin) as usize);
} else {
npart_per_dir.push(0);
}
}
assert_eq!(cum_cap, total_cap);
assert_eq!(npart_per_dir.iter().sum::<usize>(), DRIVE_NPART);
// For all directories that have too many primary partitions,
// move that partition to secondary
for (idir, (parts, tgt_npart)) in dir_prim.iter_mut().zip(npart_per_dir.iter()).enumerate()
{
while parts.len() > *tgt_npart {
let part = parts.pop().unwrap();
if !part_sec[part].contains(&(idir as Idx)) {
part_sec[part].push(idir as Idx);
}
}
}
// Calculate the vector of primary partition dir index
let mut part_prim = vec![None; DRIVE_NPART];
for (idir, parts) in dir_prim.iter().enumerate() {
for part in parts.iter() {
assert!(part_prim[*part].is_none());
part_prim[*part] = Some(idir as Idx)
}
}
// Calculate a vector of unassigned partitions
let mut unassigned = part_prim
.iter()
.enumerate()
.filter(|(_, dir)| dir.is_none())
.map(|(ipart, _)| ipart)
.collect::<Vec<_>>();
// For all directories that don't have enough primary partitions,
// add partitions from unassigned
for (idir, (parts, tgt_npart)) in dir_prim.iter_mut().zip(npart_per_dir.iter()).enumerate()
{
assert!(unassigned.len() >= *tgt_npart - parts.len());
for _ in parts.len()..*tgt_npart {
let new_part = unassigned.pop().unwrap();
part_prim[new_part] = Some(idir as Idx);
part_sec[new_part].retain(|x| *x != idir as Idx);
}
}
// Sanity checks
assert!(part_prim.iter().all(|x| x.is_some()));
assert!(unassigned.is_empty());
let part_prim = part_prim
.into_iter()
.map(|x| x.unwrap())
.collect::<Vec<_>>();
assert!(part_prim.iter().all(|p| data_dirs
.get(*p as usize)
.and_then(|x| x.capacity())
.unwrap_or(0)
> 0));
Ok(Self {
data_dirs,
part_prim,
part_sec,
})
}
pub(crate) fn data_dir(&self, hash: &Hash) -> PathBuf {
todo!()
/*
let mut path = self.data_dir.clone();
pub(crate) fn primary_data_dir(&self, hash: &Hash) -> PathBuf {
let ipart = self.partition_from(hash);
let idir = self.part_prim[ipart] as usize;
self.data_dir_from(hash, &self.data_dirs[idir].path)
}
pub(crate) fn secondary_data_dirs<'a>(&'a self, hash: &'a Hash) -> impl Iterator<Item=PathBuf> + 'a {
let ipart = self.partition_from(hash);
self.part_sec[ipart]
.iter()
.map(move |idir| self.data_dir_from(hash, &self.data_dirs[*idir as usize].path))
}
fn partition_from(&self, hash: &Hash) -> usize {
u16::from_be_bytes([
hash.as_slice()[DPART_BYTES.0],
hash.as_slice()[DPART_BYTES.1]
]) as usize % DRIVE_NPART
}
fn data_dir_from(&self, hash: &Hash, dir: &PathBuf) -> PathBuf {
let mut path = dir.clone();
path.push(hex::encode(&hash.as_slice()[0..1]));
path.push(hex::encode(&hash.as_slice()[1..2]));
path
*/
}
}
}
impl InitialFormat for DataLayout {
const VERSION_MARKER: &'static [u8] = b"G09bmdl";
}
impl DataDir {
pub fn capacity(&self) -> Option<u64> {
match self.state {
DataDirState::Active { capacity } => Some(capacity),
_ => None,
}
}
}
fn make_data_dirs(dirs: &DataDirEnum) -> Result<Vec<DataDir>, Error> {
let mut data_dirs = vec![];
match dirs {
DataDirEnum::Single(path) => data_dirs.push(DataDir {
path: path.clone(),
state: DataDirState::Active {
capacity: 1_000_000_000, // whatever, doesn't matter
},
}),
DataDirEnum::Multiple(dirs) => {
for dir in dirs.iter() {
let state = match &dir.capacity {
Some(cap) if dir.read_only == false => {
DataDirState::Active {
capacity: cap.parse::<bytesize::ByteSize>()
.ok_or_message("invalid capacity value")?.as_u64(),
}
}
None if dir.read_only == true => {
DataDirState::ReadOnly
}
_ => return Err(Error::Message(format!("data directories in data_dir should have a capacity value or be marked read_only, not the case for {}", dir.path.to_string_lossy()))),
};
data_dirs.push(DataDir {
path: dir.path.clone(),
state,
});
}
}
}
Ok(data_dirs)
}
fn dir_not_empty(path: &PathBuf) -> Result<bool, Error> {
for entry in std::fs::read_dir(&path)? {
let dir = entry?;
if dir.file_type()?.is_dir()
&& dir
.file_name()
.into_string()
.ok()
.and_then(|hex| hex::decode(&hex).ok())
.map(|bytes| (2..=4).contains(&bytes.len()))
.unwrap_or(false)
{
return Ok(true);
}
}
Ok(false)
}

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@ -125,15 +125,19 @@ impl BlockManager {
replication: TableShardedReplication,
system: Arc<System>,
) -> Arc<Self> {
// TODO don't panic, report error
let layout_persister: Persister<DataLayout> =
Persister::new(&system.metadata_dir, "data_layout");
let data_layout = match layout_persister.load() {
Ok(mut layout) => {
layout.update(&data_dir);
layout.update(&data_dir).expect("invalid data_dir config");
layout
}
Err(_) => DataLayout::initialize(&data_dir),
Err(_) => DataLayout::initialize(&data_dir).expect("invalid data_dir config"),
};
layout_persister
.save(&data_layout)
.expect("cannot save data_layout");
let rc = db
.open_tree("block_local_rc")
@ -602,7 +606,7 @@ impl BlockManager {
/// Utility: gives the path of the directory in which a block should be found
fn block_dir(&self, hash: &Hash) -> PathBuf {
self.data_layout.data_dir(hash)
self.data_layout.primary_data_dir(hash)
}
/// Utility: give the full path where a block should be found, minus extension if block is

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@ -473,10 +473,7 @@ impl BlockStoreIterator {
.data_layout
.data_dirs
.iter()
.filter_map(|x| match x.state {
DataDirState::Active { capacity } => Some(capacity),
_ => None,
})
.filter_map(|x| x.capacity())
.min()
.unwrap_or(0);
@ -484,10 +481,7 @@ impl BlockStoreIterator {
.data_layout
.data_dirs
.iter()
.map(|x| match x.state {
DataDirState::Active { capacity } => capacity,
_ => min_cap, // approximation
})
.map(|x| x.capacity().unwrap_or(min_cap /* approximation */))
.sum::<u64>() as u128;
let mut cum_cap = 0;