Hi all,
Situation:
We have a db with 1 TB of data in one .mdf file (sql 2012).
For better performance we want to split this file up into 4 equaly big data files on different drives.
1st guess:
Well I thought that's pretty simple, I just add 4 datafiles (.ndf) on different drives, empty my existing .mdf and drop it finaly.
Well the problem with this is, you cannot delete your .mdf file because it holds metadata (catalog) for your db.
Solution:
- I added 3 more datafiles (.ndf) with 250 GB size each, autogrow disabled, on 3 additional drives (no new filegroup)
- DBCC SHRINKFILE (your_logical_mdf_file, EMPTYFILE)
(this gives you an error because there is not enough diskspace to split the 1TB .mdf file into 3 x 250 GB .ndf files, but it splits your 1 TB file equaly to all your 4 db files)
- shrinked my .mdf file and adjusted filesize and autogrow settings for all 4 db files
Remark:
Just keep in mind that moving 1 TB of data around takes a while and you better do this in a not so busy time...
HTH
acki4711