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May 25, 2020 at 06:32 PM

How to move a large MDF file from one drive to another drive quickly?

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I need to move a 900GB MDF from one drive to another drive. I added a new 2tb drive to my server that I want to move the MDF into.

I tried copying multiple ways with no real luck and ended up just bringing it back online where it was.

Here's the speeds I was seeing, SQL services were stopped during the attempted copy.

  1. File explorer fluctuating between 1-10 mb/sec (gave up after about 5 minutes since it didn't speed up)
  2. robocopy, did not give a time, but after about 3 minutes I was at only .1% and after a few more minutes it went to .2% (gave up after about 5 minutes)
  3. using a second server and UNC $ paths, speed was 10-15 mb/sec (gave up after 5 minutes)
  4. Teracopy freeware app seemed to be about the same as file explorer.

I am not sure why the speeds are so slow. I had a 1.5gb installer file out on the server, I copied that into the new drive, using file explorer I copied that at 75mb/sec however when using another server using the UNC paths, I copied at 750Mb/sec according to file explorer. So it is strange that using the UNC paths I was able to get a faster speed.

Any ideas on how to copy it over? I don't want to log ship it over, I already have replication running on that DB.