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Archive for the ‘Synchronisation’ Category

Automating process monitor data collection

July 10, 2014 Leave a comment

Recently I needed to investigate why SSAS synchronisation commands were intermittently failing and the errors pointed to a file lock on a SSAS data file. To identify the file lock I needed to run process monitor for as long as it takes to capture the problem even if it takes weeks or months for it to occur. This presents the following problems

  • How to prevent the process monitor capture from consuming all available disk space.
  • How to ensure we do not over write the data we are looking for.
  • How to ensure the capture stops once we have the data we are looking for.

Read more…

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Windows 2008 file transfer performance improvements

October 9, 2012 Leave a comment

I have been reading about Server Message Block (SMB) 3 and thought to myself it would be good to remind people about SMB 2 as many systems have not upgraded to Windows 2008 to take advantage of it.

For more background on SMB, please see this article.

When Microsoft introduced SMB 2 they pretty much started again. During one of my recent migrations I found that the file copy improvements from Windows 2008 R2 have literally been jaw dropping and the highlights are. Read more…

SSAS Multithreaded sync with Windows 2008 R2

July 7, 2012 10 comments

We have been happily running some of our systems on Wndows 2003 and have had an upgrade to W2K8 R2 on the list for quite some time. The upgrade has now completed and we can start taking advantage of some of the new features which is the reason for this post.

For a long time we have used the sample Robocopy script from the SQLCat team to synchronize some of our larger SSAS databases. If your wondering what i mean by large, around 5 TB with a good few thousand partitions.

The script works like a dream but at this scale you soon find that the copy process starts to chug when it hits the fact data as this fantastic multi threaded script now becomes single threaded again as the bulk of the data being transferred is fact data.

Read more…

SSAS – Synchronisation performance

April 8, 2010 Leave a comment

I’ve always thought of SSAS synchronisation as a clever file mirroring utility built into SSAS and i have never considered the technology as bringing any performance gains to the table. So, its a good job I like to revisit areas…. 🙂

I decided to compare the performance of robocopy and SSAS Synchronisation between 2 Windows 2003 servers running SSAS 2008 SP1 CU7 with 1gb network links. For the robocopy of the data directory i used the SQLCat Robocopy Script. The results are shown below.
   

  SSAS Sync Robocopy
Full DB (138gb) 58 min 96 min
Single Partition (10gb) 3 min 37s 7 min 46s

The Full DB copy is as it says, no data is present so synchronise the lot.

Single Partition is where after the full db is processed i then process a single partition (and yes the partition is around 10gb) and then run the synchronisation.

The results left me gobsmacked! At first i simply could not believe that the SSAS sync could copy the data that much faster than robocopy but i repeated my tests a number of times and it does!

Yes, SSAS Synchronisation is between 100% and 50% faster than Robocopy… I’ve got to say that when Microsoft did the rewrite for 2008 they certainly did a fine job!

Before I finish up with this blog entry I must say there are always considerations as to whether synchronisation is appropriate for you and i will be posting soon about all the different options and the considerations.