Date: Wed, 22 Oct 2003 17:26:51 -0400 From: Ryan Sandridge <ryansandridge@ryansandridge.com> To: Dave McCammon <davemac11@yahoo.com> Cc: freebsd-questions@freebsd.org Subject: Re: strange dump (dark matter?) Message-ID: <7381BDDB-04D6-11D8-AAFC-003065BBC750@ryansandridge.com> In-Reply-To: <20031022200054.30862.qmail@web41412.mail.yahoo.com> References: <20031022200054.30862.qmail@web41412.mail.yahoo.com>
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On Oct 22, 2003, at 4:00 PM, Dave McCammon wrote: > > --- Ryan Sandridge <ryan@sandridge.org> wrote: >> Hello all. I decided it was time to start doing >> backups. On Oct 7th, >> I did a full dump of /usr filesystem (among others), >> as such: >> # dump -0uan -f - /usr | gzip -7 > >> /tmp/20031007-usr-lvl0.dump.gz >> >> This seemed to work as expected, here is some info >> about the gz file: >> % gzip -l 20031007-usr-lvl0.dump.gz >> compressed uncompr. ratio uncompressed_name >> 507027476 1590855680 68.1% 20031007-usr-lvl0.dump >> >> Everything so far so good. Today (Oct 22) I tried >> an incremental dump, >> as such: >> # dump -5uan -f - /usr | gzip -7 > >> /tmp/20031022-usr-lvl5.dump.gz >> >> Here is where I start getting confused. While my >> other incremental >> backups today (/ and /var), seemed to be fine, the >> /usr dump was huge. >> Here is info about the gz file: >> % gzip -l 20031022-usr-lvl5.dump.gz >> compressed uncompr. ratio uncompressed_name >> 527112624 543600640 3.0% 20031022-usr-lvl5.dump >> >> This incremental backup is larger than the original >> full dump. Also >> notice that the compression ratio was 3.0%. When >> examining the list of >> files dumped, I don't see anything that could lead >> to a file size like >> this. A rough count shows that the backup should >> have been roughly >> 11MB uncompressed, compared to the 518MB >> uncompressed. I've tried >> reading up on both dump and gzip, but haven't found >> a clue. Perhaps >> I've discovered dark matter. >> >> Thanks, >> Ryan > > Where is the file of your first backup stored? > Did it get backed up as part of the incremental > backup? I should have mentioned that I had checked that already, because that would almost explain the unaccounted for 507 MB... but unless I'm missing something, that is not the problem. The backups were made onto /tmp filesystem, which were then archived to cd-rom, and deleted from /tmp. Ah, might be onto something though... I made an .iso file containing the dumps, which was copied to my home directory before burning to cd. That .iso file sat there until today, but was deleted before I did today's dump. So, I suppose it is possible that the filesystem wasn't flushed (is that what its called?), so the file was still there. I presume, however, this would be a bug with dump, as that .iso file is NOT in the archive. Do you think this is what happened? Thanks, Ryan
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