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I've been attempting to figure out this problem for quite some time and have looked at all the normal solutions. I am attempting to run a .backup on an sqlite database. I don't think it matters, but this particular database is being used by Membase and is also running on the Amazon cloud. Both the folder that I am backing up to, and the folder that the database is coming from has 777 permissions (which is the normal cause of this message). If I sudo the backup command, it gets partway through the backup and then the process just hangs while consuming CPU usage and leads me to eventually kill the sqlite process. I even went through and chmod 777 the database file itself.

Here is whats happening:

/opt/membase/bin/sqlite3 /mnt/data-store/default-data/default-0.mb '.backup /mnt/data-backup/mbfiles/test.mb'

Error: unable to open database file

When I ls -la the folder:

drwxrwxrwx 2 membase membase      4096 Sep 10 15:41 .
drwxrwxrwx 4 membase root         4096 Aug  5 01:10 ..
-rw-r--r-- 1 membase membase     53248 Sep 10 15:41 default
-rwxrwxrwx 1 membase membase 849593344 Sep 10 15:41 default-0.mb

And the backup folder:

drwxrwxrwx 2 ec2-user ec2-user 4096 Sep 10 15:41 .
drwxrwxrwx 4 root     root     4096 Sep  3 00:26 ..

Also, because I hear it matters, the permission of /tmp

drwxrwxrwt  3 root root 4096 Sep 10 03:32 .

I've been trying to fix this for over a week now, and any new ideas would be appreciated. It should be noted that this is a production environment so restarting is not an option.

EDIT: I checked and I can back up the smaller "default" file, just not the larger db, so this rules out any sort of issue with folder permissions. Any help would be hugely appreciated.

Thanks!

benRollag
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David
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1 Answers1

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This seems like an sqlite issue. We've seen sporadic occurrences of this error at other customers but have not been able to track it down or resolve it yet. According to the sqlite experts, this should never happen ;-)

Can you shutdown the Membase process to test further? If so, trying to take a backup (make sure the 'memcached' process is stopped) at this point would rule out any issue with software accessing the file. If it still doesn't work at this point, I know there are tools to verify a sqlite DB (just don't have them off the top of my head).

You can also use a combo of ".dump" and ".restore" via sqlite, but I wouldn't recommend running that on a running Membase node as we haven't tested out the effects.

Perry

Perry Krug
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