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Re: Linux Kernel Summit

From: Jim Blandy <jimb_at_zwingli.cygnus.com>
Date: 2001-04-02 13:24:00 CEST

Greg Stein <gstein@lyra.org> writes:
> * Use some kind of checksum on the wire and in the DB. Given that whatever
> is in source control is probably quite important, it would be a Good Thing
> if we hashed/checksummed the data. Even better if we periodically reviewed
> the whole database for items whose checksum has mysteriously changed or
> failed. The point is that bits can corrupt over the N year period that the
> data resides in source control. Catching the corruption sooner rather than
> later makes it easier to get back to a correct state. Imagine if you tried
> to get a checkin from four years ago, but it had been corrupted three
> years back? You probably don't have a valid version anywhere.
>
> I suggested that the client could compute an MD5 hash, send it over the
> wire using HTTP's Content-MD5 header, Apache would verify it (built in!),
> and that we'd place the hash into the database with the data. When the
> data is retrieved, we can send it back over the wire with Content-MD5 and
> the client can verify the hash value.

I think someone pointed this out a while back. The skels for
deltafied storage include checksums. There's no external FS interface
for retrieving them at the moment, but that's a few minutes' work.
Received on Sat Oct 21 14:36:27 2006

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