[pve-devel] [PATCH pve-storage] fix #6450: add file-checksum endpoint to storage API

[Thomas Lamprecht]

Am 02.10.25 um 14:15 schrieb Shannon Sterz:
>>              warn $@ if $@;
>>          }
>>
>> +        if (exists $param->{checksum}) {
>> +            print "calculating checksum...\n";
>> +            $entry->{checksum} = PVE::Tools::get_file_hash($param->{checksum}, $path);
> i've tested this with some not too uncommon disk images such as a 32GB
> volume that is essentially empty and the api endpoint here just times
> out. which is not too surprising. i wonder if we can cache the hashes
> here somehow and calculate them in a worker tasks. i also wonder how
> this should ideally work for running vm and container images as their
> checksum could change all the time.
> 
> maybe we can at least calculate the hashes here for some more static
> assets such iso etc. ahead of time and only enable this flag for things
> like that (so isos, container templates, images of vm and container
> templates etc.) basically things that don't change that much?


I could not find it, but IIRC there was such a request (or patch?) for
checksums of storage content submitted in the past where we discussed
this already.

Anyhow, this is really not something trivial and would need some system
to cache the hash while also having a heuristic that ensures the cached
hash is still valid – as having a wrong hash returned might needlessly
wreck some nerves of any admin that take their job seriously.

We could do a file that contains the hash(es) and a inode nr., file
size and mtime value from the time those hash(es) got created as
heuristic to detect legitimate change. Plus probably the date to
show the user that this is was not calculated on the fly.
And yes, actual calculation needs to happen in a task worker, as
this can run for quite a while on big files and/or slow storages.
So probably best done in a dedicated API call I guess, but with all
this in mind I'm questing a bit if this is really worth that much
effort...