[pbs-devel] applied: [PATCH proxmox-backup v5] datastore: make 'filesystem' the default sync-level

[Thomas Lamprecht]

Am 04/11/2022 um 10:49 schrieb Dominik Csapak:
> rationale is that it makes the backup much safer than 'none', but does not
> incur a big of a performance hit as 'file'.
> 
> here some benchmark:
> 
> data to be backed up:
> ~14GiB semi-random test images between 12kiB and 4GiB
> that results in ~11GiB chunks (more than ram available on the target)
> 
> PBS setup:
> virtualized (on an idle machine), PBS itself was also idle
> 8 cores (kvm64 on Intel 12700k) and 8 GiB memory
> 
> all virtual disks are on LVM with discard and iothread on
> the HDD is a 4TB Seagate ST4000DM000 drive, and the NVME is a 2TB
> Crucial CT2000P5PSSD8
> 
> i tested each disk with ext4/xfs/zfs (default created with the gui)
> with 5 runs each, inbetween the caches are flushed and the filesystem synced
> i removed the biggest and smallest result and from the remaining 3
> results built the average (percentage is relative to the 'none' result)
> 
> result:
> 
> test         none     filesystem         file
> hdd - ext4   125.67s  140.39s (+11.71%)  358.10s (+184.95%)
> hdd - xfs    92.18s   102.64s (+11.35%)  351.58s (+281.41%)
> hdd - zfs    94.82s   104.00s (+9.68%)   309.13s (+226.02%)
> nvme - ext4  60.44s   60.26s (-0.30%)    60.47s (+0.05%)
> nvme - xfs   60.11s   60.47s (+0.60%)    60.49s (+0.63%)
> nvme - zfs   60.83s   60.85s (+0.03%)    60.80s (-0.05%)
> 
> So all in all, it does not seem to make a difference for nvme drives,
> for hdds 'filesystem' increases backup time by ~10%, while
> for 'file' it largely depends on the filesystem, but always
> in the range of factor ~3 - ~4
> 
> Note that this does not take into account parallel actions, such as gc,
> verify or other backups.
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
> changes from v4:
> * included benchmark & rationale in the commit message
> 
>  docs/storage.rst               | 4 ++--
>  pbs-api-types/src/datastore.rs | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
>

applied, thanks!