You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@subversion.apache.org by "D.J. Heap" <dj...@dhiprovo.com> on 2003/08/27 17:50:56 UTC
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin list-dblogs
and list-unused-dblogs commands
There's still the nasty little race in here where a log file that wasn't
backed up could be deleted, right? Like when the recovery step takes a
while and another commit comes in -- the new hotbackup hasn't had time
to copy yet, the current one finishes recovery and starts whacking log
files that it may not have copied.
I think that can be fixed by making sure only the log files that were
copied in step 3 are deleted in step 6 -- don't delete everything
db_archive reports, just the union of what it reports and what we copied...
Or am I missing something?
DJ
**********************************************************************
This email and any files transmitted with it are confidential
and intended solely for the use of the individual or entity to
whom they are addressed. If you have received this email
in error please notify the system manager.
This footnote also confirms that this email message has been
swept by MIMEsweeper for the presence of computer viruses.
www.mimesweeper.com
**********************************************************************
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin list-dblogs
and list-unused-dblogs commands
Posted by Vladimir Berezniker <vm...@tigris.org>.
Philip Martin wrote:
<snip>
> The fact that our current backup script has a problem indicates that
> it's possible to get the backup procedure wrong. I like the idea of
> having a standard, robust, reliable method of making a hot backup.
> The question is whether it is better to script it, or to make it a
> standard command. Scripting has the advantage that it can more easily
> be customised, but that also allows it to be broken.
>
> On the whole I am in favour of an 'svnadmin copy' command.
>
Just to clarify. The command I am working on will make a hot copy of a
repository. To do backups a user could wrap copy command in a script.
For example, to retain the latest 64 copies, like hot-backup.py does.
This way user does not need to know how to make a hot copy, but it
leaves user free to script the backup any way they want. Well at least
as long as they can make a copy first. :)
Sincerely,
Vladimir Berezniker
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin
list-dblogs and list-unused-dblogs commands
Posted by Philip Martin <ph...@codematters.co.uk>.
Vladimir Berezniker <vm...@tigris.org> writes:
> D.J. Heap wrote:
>
>> There's still the nasty little race in here where a log file that
>> wasn't backed up could be deleted, right? Like when the recovery
>> step takes a while and another commit comes in -- the new hotbackup
>> hasn't had time to copy yet, the current one finishes recovery and
>> starts whacking log files that it may not have copied.
>> I think that can be fixed by making sure only the log files that
>> were copied in step 3 are deleted in step 6 -- don't delete
>> everything db_archive reports, just the union of what it reports and
>> what we copied...
>> Or am I missing something?
>> DJ
>>
> <snip>
>
> I have mentioned this in about 3 emails, and provided hypothetical
> scenario how it could happen. However, I have not gotten a response
> as of yet. I guess this would only be applicable when total
> corruption occurs, so that all logs from the point of the previous
> good backup have to be replayed.
I agree, I think it's a real bug.
> I also offered to create a builtin hotcopy command and have not
> gotten much of a response on that either. However, I did see the
> email about the fact how everyone wants to add new exciting features
> to subversion and developers are stuck finding and fixing bugs.
> Since, after looking through bite-sized issues, I could not find a
> single one that I could work on. I decided it would be inappropriate
> for me to keep pushing the hotcopy thing.
The fact that our current backup script has a problem indicates that
it's possible to get the backup procedure wrong. I like the idea of
having a standard, robust, reliable method of making a hot backup.
The question is whether it is better to script it, or to make it a
standard command. Scripting has the advantage that it can more easily
be customised, but that also allows it to be broken.
On the whole I am in favour of an 'svnadmin copy' command.
--
Philip Martin
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin
list-dblogs and list-unused-dblogs commands
Posted by Greg Hudson <gh...@MIT.EDU>.
On Wed, 2003-08-27 at 14:12, Vladimir Berezniker wrote:
> I also offered to create a builtin hotcopy command and have not gotten much of a
> response on that either. However, I did see the email about the fact how
> everyone wants to add new exciting features to subversion and developers are
> stuck finding and fixing bugs. Since, after looking through bite-sized issues,
> I could not find a single one that I could work on. I decided it would be
> inappropriate for me to keep pushing the hotcopy thing.
Well, if doing it externally leads to a race condition, and this is the
easiest way to fix it, then you're fixing a bug, so I'd say that's
fine. (But I really don't understand the issue well enough to be sure.)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin list-dblogs and list-unused-dblogs commands
Posted by cm...@collab.net.
Vladimir Berezniker <vm...@tigris.org> writes:
> I have mentioned this in about 3 emails, and provided hypothetical
> scenario how it could happen. However, I have not gotten a response
> as of yet.
Here's a response: if we have race condition, we need to fix it.
> I also offered to create a builtin hotcopy command and have not
> gotten much of a response on that either.
Here's a reponse: make it happen.
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Re: [PATCH] Convert hot-backup.py.in to use new svnadmin list-dblogs
and list-unused-dblogs commands
Posted by Vladimir Berezniker <vm...@tigris.org>.
D.J. Heap wrote:
> There's still the nasty little race in here where a log file that wasn't
> backed up could be deleted, right? Like when the recovery step takes a
> while and another commit comes in -- the new hotbackup hasn't had time
> to copy yet, the current one finishes recovery and starts whacking log
> files that it may not have copied.
>
> I think that can be fixed by making sure only the log files that were
> copied in step 3 are deleted in step 6 -- don't delete everything
> db_archive reports, just the union of what it reports and what we copied...
>
> Or am I missing something?
>
> DJ
>
>
<snip>
I have mentioned this in about 3 emails, and provided hypothetical scenario how
it could happen. However, I have not gotten a response as of yet. I guess this
would only be applicable when total corruption occurs, so that all logs from the
point of the previous good backup have to be replayed.
I also offered to create a builtin hotcopy command and have not gotten much of a
response on that either. However, I did see the email about the fact how
everyone wants to add new exciting features to subversion and developers are
stuck finding and fixing bugs. Since, after looking through bite-sized issues,
I could not find a single one that I could work on. I decided it would be
inappropriate for me to keep pushing the hotcopy thing.
Sincerely,
Vladimir Berezniker
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org