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

[Daniel Tschlatscher]

Talked with Dominic off-list:

I had a bit of an error in reasoning with the usage of 'available' here 
which means
it does not work quite as I expected here.

Therefore, please ignore this patch. I will try to re(think) and rewrite 
this patch in v2.

The first patch should still be applicable though, as it does not impact 
any of this.

On 5/27/22 12:57, Daniel Tschlatscher wrote:
> 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 at 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);