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From Alex P <apede...@kolosy.com>
Subject Re: couch behavior for san snapshots
Date Mon, 19 Oct 2009 19:37:40 GMT
i'll take a peek tonight, but it just doesn't sound like corruption. the db
is visible, readable, writable, just has an update sequence of 0, 0 docs and
a db size (as reported by futon) of 4.0kb.

is db size computed off the file size, or based on actual contents? because
if it's the file size, it really doesn't sound like corruption...

(fwiw this is a separate, yet similar issue from the one i had earlier with
data disappearing from a live system)

On Mon, Oct 19, 2009 at 2:35 PM, Alex P <apedenko@kolosy.com> wrote:

> cdb catalogs databases purely on file name and presence in the appropriate
> directory, right? so if i copy db1 to db1_copy, i should see db1_copy show
> up in futon?
>
>
> On Mon, Oct 19, 2009 at 2:23 PM, Paul Davis <paul.joseph.davis@gmail.com>wrote:
>
>> On Mon, Oct 19, 2009 at 3:18 PM, Alex P <apedenko@kolosy.com> wrote:
>> > hello,
>> >
>> > we ran into an issue this weekend where taking a SAN (amazon ebs)
>> snapshot
>> > of a couchdb mount somehow brought over only part of the data.
>> specifically,
>> > there were two small dbs (call them db1 and db2) on the couch instance,
>> each
>> > with several hundred documents. taking the snapshot and bringing it up
>> again
>> > showed both databases, but one had 0 documents and an update sequence of
>> 0.
>> > the instance the snapshot was taken from still has both databases
>> showing
>> > with several hundred databases. we repeated this process several times,
>> with
>> > the same effect, on the same db.
>> >
>> > any thoughts would be much appreciated, as we are about to go live, and
>> not
>> > being able to do a backup of our db is ... disturbing.
>> >
>> > thanks,
>> > alex.
>> >
>>
>> Alex,
>>
>> That's most odd. What happens if you try and cp the database file to a
>> new name? Something like:
>>
>> $ cp /usr/local/var/lib/couchdb/db1.couch
>> /usr/local/var/lib/couchdb/db3.couch
>>
>> Another thing to try would be:
>>
>> $ curl -X POST http://127.0.0.1:5984/db1/_ensure_full_commit
>>
>> And then try to snapshot or copy again. I highly doubt that POST would
>> affect anything, but it might be worth a shot.
>>
>> Paul Davis
>>
>
>

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