May 20, 2003 at 10:04 am
At our site, the NTFS file creation portion of a SQL 2000 SP3 database restore generally takes a long time despite the fact that we use EMC disk storage and 4-way 2.0 GHz servers. Our latest example was a 45 GB restore via Enterprise Manager. When the restore started out, it generated the 45 GB .mdf and 144 MB .ldf NTFS files rather quickly (somewhere within the first 10 or 15 minutes), but then the restore stopped reading the tape, presumably to do something with the .mdf and .ldf files it just created. 4 [sic] hours later, it started reading the tape and displaying blue “chicklets” on the “Restore Progress” window. The restore is still running, and I presume that it will take another 1.5 hours to put the tape on disk since it took that long to backup the database in the first place.
Can anyone shed any light on how to speed up the creation of the NTFS files and/or reduce the amount of “wait time” for SQL to start reading the tape and applying its contents to disk? All suggestions are appreciated.
Thanks,
Jon
Edited by - shew01 on 05/20/2003 10:06:51 AM
May 20, 2003 at 10:37 am
From what I understand, once the mdf is created, it is Zeroed out to ensure the state of the file. This is what takes the time.
Steve Jones
May 20, 2003 at 10:45 am
I think you are right. It seems like I read something about that a while back. Do you have any ideas on how to "encourage the process along" a bit? It just seems silly to me to spend 4 hours on zeroing out something that will be restored anyway... Am I missing something?
Jon
May 21, 2003 at 6:54 am
Some format jobs give you the option of Quick Format or Long Format. If you haven't tried it, Quick format takes a very short time, Long format can take a hour for a floppy disk.
So, what appears to be happening, is that the restore 'grabs' the amount of space it needs for the files, does a long (or complete) format and then starts the restore. It probably also checks to make sure there's no data in the space that it 'grabbed' for the .mdf and .ldf files.
-SQLBill
Viewing 4 posts - 1 through 3 (of 3 total)
You must be logged in to reply to this topic. Login to reply