[pbs-devel] [PATCH proxmox-backup 1/1] fix #4077: Estimated Full metric on ext4 file systems

[Daniel Tschlatscher <d.tschlatscher@proxmox.com>]

The estimated full statistics metric no longer uses the total amount
of space on a disk, but rather the still available. Also refactored
some variable names for the 'estimated_full' calculation to make it
clearer what changed/is used now.

Note: Statistics for 'available' were not tracked in the rrdb before,
existing datastores will therefore show a somewhat incorrect value for
'estimated_full', at least until it is populated with enough new
values.

Signed-off-by: Daniel Tschlatscher <d.tschlatscher@proxmox.com>
---
 src/api2/status.rs              | 14 +++++++-------
 src/bin/proxmox-backup-proxy.rs |  2 ++
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/api2/status.rs b/src/api2/status.rs
index 45aa7fd7..f7d96c49 100644
--- a/src/api2/status.rs
+++ b/src/api2/status.rs
@@ -88,25 +88,25 @@ pub fn datastore_status(
         let get_rrd =
             |what: &str| extract_rrd_data(&rrd_dir, what, RRDTimeFrame::Month, RRDMode::Average);
 
-        let total_res = get_rrd("total")?;
+        let avail_res = get_rrd("available")?;
         let used_res = get_rrd("used")?;
 
-        if let (Some((start, reso, total_list)), Some((_, _, used_list))) = (total_res, used_res) {
+        if let (Some((start, reso, avail_list)), Some((_, _, used_list))) = (avail_res, used_res) {
             let mut usage_list: Vec<f64> = Vec::new();
             let mut time_list: Vec<u64> = Vec::new();
             let mut history = Vec::new();
 
             for (idx, used) in used_list.iter().enumerate() {
-                let total = if idx < total_list.len() {
-                    total_list[idx]
+                let available = if idx < avail_list.len() {
+		    avail_list[idx]
                 } else {
                     None
                 };
 
-                match (total, used) {
-                    (Some(total), Some(used)) if total != 0.0 => {
+                match (available, used) {
+                    (Some(available), Some(used)) if available != 0.0 => {
                         time_list.push(start + (idx as u64) * reso);
-                        let usage = used / total;
+                        let usage = used / available;
                         usage_list.push(usage);
                         history.push(Some(usage));
                     }
diff --git a/src/bin/proxmox-backup-proxy.rs b/src/bin/proxmox-backup-proxy.rs
index 659f7b4a..82f40a54 100644
--- a/src/bin/proxmox-backup-proxy.rs
+++ b/src/bin/proxmox-backup-proxy.rs
@@ -1140,6 +1140,8 @@ fn gather_disk_stats(disk_manager: Arc<DiskManage>, path: &Path, rrd_prefix: &st
             rrd_update_gauge(&rrd_key, status.total as f64);
             let rrd_key = format!("{}/used", rrd_prefix);
             rrd_update_gauge(&rrd_key, status.used as f64);
+            let rrd_key = format!("{}/available", rrd_prefix);
+            rrd_update_gauge(&rrd_key, status.avail as f64);
         }
         Err(err) => {
             eprintln!("read disk_usage on {:?} failed - {}", path, err);
-- 
2.30.2