October 16, 2008 at 4:56 am
Dear All,
I have just noticed something horrible on my site. After backing up databases with LiteSpeed for some months we started using the 'DoubleClick Restore' functionality. Restoring smaller DBs went fine and everyone was happy.
Come our first DR test with the bigger DBs we noticed that all LiteSpeed backups larger then ~4.2 GB fails to open with the dreaded ' .EXE is not a valid Win32 application.'. Note that these files have all been verified successfully by the Backup verification in LiteSpeed.
Have someone else experienced this and is it horrible a bug/feature in LiteSpeed or am I just increadible unlucky?
LiteSpeed version: 4.8.4.00086
SQL Server: 2000 SP4+ (8.00.2040) Ent. Ed.
OS: Windows 2000 Advanced Server
HansLindgren
Update: The backups are still possible to be restored successfully using the normal LiteSpeed restore so it is only the DoubleClick restore that seems to be 'broken' for files larger then an INT.
October 20, 2008 at 10:33 pm
October 21, 2008 at 1:18 am
Thank you for the article!
But we have hundreds of DoubleClick archive and every single one I have tried so far, that is smaller then an unsigned INT (bytes), works. I.e. they both run and restore correctly when starting them.
Regards,
Hans
October 22, 2008 at 8:22 am
Is it possible that an executable simply cannot be allowed to load more than 4 GB of data because that's the maximum possible address space for a 32-bit system?
I would like to think that the folks that wrote LiteSpeed would know about that kind of limitation and that it would be documented somewhere.
Steve
(aka smunson)
:):):)
Steve (aka sgmunson) 🙂 🙂 🙂
Rent Servers for Income (picks and shovels strategy)
October 22, 2008 at 8:36 am
IMHO... and for future reference:
[soapbox]
I suggest avoiding any and all 3rd party backup tools for any and all versions of SQL Server. The native backup methods are the most reliable and trusted methods.
[/soapbox]
_______________
bkDBA
0.175 seconds -- 10 year average margin of victory at the Daytona 500
212 Degrees
October 29, 2008 at 7:35 pm
We have just noticed the same issue with the newest release of LiteSpeed. It was a similar surprise. And the same situation that all smaller databases are backing up fine as a double click. But databases over 4GB have corrupt double click restores. Plan to talk to ScriptLogic/Quest about this. Very disturbing given it's been happening for some time and we might have needed one of the backups.
October 29, 2008 at 7:40 pm
Here's info from Quest's web site:
Cause
MS Windows Operating System has a limitation: No Executable can be over 4Gb even on a 64-Bit MS Windows version. So the limitation of the OS restricts creating files over 4Gb which means double-click restore will not work for large databases.
Resolution
Since striping of backups is allowed with double-click Restore, it is possible to create double-click Restore sets for database backups greater than 4 gigabytes; it is the user's responsibility to estimate how many stripes are needed for this.
You can still do a striped backup, but only the first file listed in the file list will be made an executable. During a restore, the executable, and all the additional .bak files produced by the backup, must be stored in the same directory for the restore to be successful.
October 30, 2008 at 11:03 am
bkDBA: I do not really agree with where you are coming from. Maybe SQL Server 2k8 will give us the inherent backup compression needed for VLDBs but previous versions do not. Implement production level, native backups, on DBs with hundreds of GBs and you'll feel the pressure (seeing that full backups will take a bigger part of a 24 hour day).
David: Thank you! That was exactly the information I needed! FYI: our DoubleClick backups of more then 4 GB ARE restorable through the 'normal' LiteSpeed restore, even though the DoubleClick functionality is 'broken'.
Best Regards,
Hanslindgren
October 30, 2008 at 11:37 am
Hans,
Thanks for the clarification that the backups are still usable. I had significant concern about that. FYI - another Quest support post said that "stripes" can be used to break the backup into smaller chunks. And that the "first" file will be an EXE (double click restore) and it will use the other chunks. But I don't yet know how to make this work.
I also agree that tools like LiteSpeed are needed and useful. And commonly used. There is nothing wrong with them and they exist to meet a need.
David
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