[pbs-devel] [PATCH proxmox-backup] fix #5622: backup client: properly handle rate/burst parameters

[Christian Ebner]

On 8/1/24 14:44, Christian Ebner wrote:
> On 7/23/24 12:04, Dominik Csapak wrote:
>> the rate and burst parameters are integers, so the mapping from value
>> with `.as_str()` will always return `None` effectively never
>> applying any rate limit at all.
>>
>> To fix it, just map from u64 to HumanByte.
>>
>> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
>> ---
> 
> Did some tests on this and while the rate limit gets applied, the burst 
> value does not seem to be honored for my case. Am I misinterpreting the 
> burst parameter or is there still an underlying issue?
> 
> Here is what was tested:
> - Monitor network throughput to localhost by running `tcpsubnet-bpfcc 
> 127.0.0.1/32` as well as `iftop` (got only low additional traffic noise 
> without invoking the proxmox-backup-client).
> - Before each proxmox-backup-client invocation, the chunks and snapshots 
> were deleted from the datastore to have similar conditions.
> - Backup using proxmox-backup-client to local datastore via localhost by 
> running `proxmox-backup-client backup usr.pxar:/usr --rate=100000`, rate 
> limit is now honored as expected!
> - `proxmox-backup-client backup usr.pxar:/usr --rate=100000 
> --burst=1000000000000`, expected to reach much higher initial burst 
> throughput because of the huge bucket size, but rate is limited to the 
> same rate as above already from the beginning.
> - Without rate limit, much higher rates can be reached, so that is not 
> the limiting factor.

Ah, I see the bucket starts empty, so this is expected then.