[Opensim-users] Question on migrating database from Linux to Windows and vice versa
Chris Kennedy
mewtwo0641 at cox.net
Mon Jul 12 12:53:27 UTC 2010
Thank you SO much for taking the time to explain it to me =) I sincerely
appreciate it!
It has put my mind at ease about cross platform backups now... I was
always worried I'd lose the stuff that I have worked long hours to put
together on OpenSim by cross platform backups. I will continue to keep
multiple backups though, mainly several "generations" of SQL dumps and
OAR/IAR's , just to err on the side of caution. Thanks for the heads up
on OS 0.7.x as well =)
On 7/12/2010 3:09 AM, Karen Palen wrote:
> My experience is with Engineering or design type databases rather than
> commercial/SQL type of databases, however the concept of data
> integrity is so fundamental that I would be very surprised if much
> would happen without being noticed!
>
> In the case of MySql you are essentially running the same software in
> different environments - both the basic database server and the Admin
> tools - so I would expect any major issues to be a very rare things.
>
> Probably the best assurance of this is the MySql "market share", it is
> one of the most popular database systems in existence and is used in
> all kinds of environments (OS, hardware, networks, etc.) from simple
> standalone setups to massive distributed corporate "enterprise"
> systems. As a result I would expect that any common problems would be
> found and fixed very rapidly.
>
> The kind of data loss caused by parts of a file being deleted could
> certainly occur, but there are very well known and widely used methods
> to detect and fix this kind of problem. My recollection is that the
> SQL "backups" from MySql have several built in mechanisms to check this.
>
> Loss of some more subtle information such as a pointer to a specific
> texture (or your other examples) is more likely, however the
> application software would (SHOULD!) be the same version of OpenSim in
> both cases so this too is very unlikely. This however is a distinct
> possibility when upgrading from one version to the next regardless of
> the OS!
>
> Since there are extensive changes made to the internal workings of
> OpenSim between V0.6.9 and V0.7.xx this becomes very plausible. It is
> the subject of a lot of the testing work being done on the current RCs
> as a result. Again I would expect that by the time V0.7 is released
> the major problems either fixed or well known.
>
> All the same any grid that has more than a half dozen users will
> likely implement its own beta testing program to catch these problems
> in your specific environment. There always do seem to be a few issues
> brought to light in these tests! Not a problem if you only need to fix
> up two or three users (or regions) but if say 5000 users have their
> inventory corrupted then you have a major problem!
>
> As always "slow and easy wins the race" and a well planned step by
> step migration is essential.
>
> Karen
>
> On Sun, Jul 11, 2010 at 6:28 PM, Chris Kennedy <mewtwo0641 at cox.net
> <mailto:mewtwo0641 at cox.net>> wrote:
>
> I do make seperate OAR and IAR backups along side my SQL dumps =)
>
> I was just wondering if there would be any definite data loss when
> saving and restoring these SQL dumps across multiple platforms...
> or if data loss would be a "freak" kind of thing (i.e. a bug in
> the My SQL server or MySQL Admin when it comes to Linux or
> Windows, or configuration differences between the default setup of
> the MySQL server on Linux vs. Windows, etc).
>
> Would it be a noticeable thing if data loss did occur such as
> missing inventory, or something more subtle that would take a bit
> of digging to find; such as missing textures or even "blank" data
> (i.e. open a texture and all you see is a white box where the
> texture should have been. Or try to play an animation / sound from
> your inventory and it won't play)?
>
> Thank you very much for the suggestions! =)
>
>
> On 7/11/2010 7:25 PM, Karen Palen wrote:
>> I don't have a lot of experience with porting MySql between
>> different OSes, but general "belt and suspenders" considerations
>> says that a second and independent path would be a very good
>> "safety net".
>>
>> I would definitely suggest making an IAR backup of every user
>> inventory and an OAR backup of every region! In that way you have
>> a totally separate way to transfer the data and at least the
>> opportunity to recover anything which is corrupted or lost in the
>> transfer!
>>
>> I believe there are tutorials on how to automate these backups
>> although I have not personally tried them. If you have more that
>> 2 or 3 users and/or 2 or 3 regions then this will significantly
>> reduce the workload.
>>
>> It pays to be VER conservative (careful) in making backups since
>> if information is LOST it can be extremely hard to re-create,
>> finding something in multiple backups is trivial compared to
>> re-creating content!
>>
>> remember: Jesus saves - EARLY AND OFTEN!
>>
>> Karen
>>
>> On Sun, Jul 11, 2010 at 4:22 PM, Chris Kennedy
>> <mewtwo0641 at cox.net <mailto:mewtwo0641 at cox.net>> wrote:
>>
>> Hi, I want to migrate my OpenSim MySQL database from Linux to
>> Windows and vice versa (for traveling reasons) using the
>> MySQL Admin's SQL dump ( MySQL Admin Backup) feature.
>>
>> Is there anything special that I need to know or to look out
>> for when doing this (besides making sure Max Packet Size is
>> set to 16 MB on the target system)?
>>
>> The way I normally do my database backup in the Linux
>> environment is to shut down the OpenSim server, go to the
>> backup tool in MySQL Admin, create a backup project (if it
>> doesn't already exist) for my OpenSim schema making sure all
>> the tables are selected for backup. Then I go into advanced
>> options and click on Normal Backup, and check Complete Backup
>> and run the backup to save my database to a .sql file. This
>> method has worked perfectly fine for me under Linux with no
>> data loss after a restore from backup that I can tell. I have
>> even restored my database to a Windows environment from a
>> Linux created MySQL dump file with no problems that I can see.
>>
>> My concern is creating a database backup in a Windows
>> environment and then restoring it to Linux (or even another
>> Windows environment). Would this, under normal circumstances,
>> cause data loss?
>>
>> The reason I ask is: I have successfully been able to restore
>> my Windows created SQL dump file to Linux and other Windows
>> systems running XP... But the moment I try to restore my
>> database to a Windows 7 system I get an error that says
>> "Object Type not recognized" (or it might have said Object
>> Type not Found, I don't remember off the top of my head) and
>> the restore fails.
>>
>> In a nutshell, is it safe to port my backups between
>> different operating systems like this? Or am I better off
>> creating OARs of my regions and IAR of my inventory(s)? I
>> always make both OAR/IAR and SQL dump backups just to be
>> safe, but I would like to know.
>>
>> Any suggestions and/or tips would be much appreciated! =)
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