Re: Corrupt cache or what else could cause this?
Hendrik Visage <[email protected]>
| Newsgroups | gmane.org.operators.ioz |
|---|---|
| Message-ID | <[email protected]> |
On Sun, Mar 13, 2011 at 9:31 PM, Roland Giesler <[email protected]>wrote: > > This points to a corrupt cached copy somewhere, doesn't it? > > Doesn't the checksumming in a cache server prevent this kind of thing > from happening? > What checksumming in the cache servers? The hashing typically done inside cache servers, is on the URL to "compress" it and make it more manageable in computer storage terms. > Surely a cache server is clever enough to see that it's copy is not the > same as the one requested? > How? By re-downloading the same file, thus not caching? The upstream could touch/change the date on the file, that way the upstream could "force" a refetch if the cache time have expired. Yes, cache "corruption" can happen, especially when they've received a bad copy from upstream (read: solar flares ;) but more so when a download manager asks for several pieces at once, and the upstream gives an error half way through a transfer. I've seen a case many summers ago that cached a page with the error at the bottom of the partial HTML. What would be nice/interesting is to redo the wget, but with the needed pragma=no-cache etc. to attempt a single threaded cache-bypass request. _______________________________________________ IOZ mailing list [email protected] http://lists.internet.org.za/mailman/listinfo/ioz