'vlf'에 해당되는 글 1건

  1. VLF 생성 알고리즘 변경 SQL2014 이후 버젼 (1)


http://www.sqlskills.com/blogs/paul/important-change-vlf-creation-algorithm-sql-server-2014/


For SQL Server 2014, the algorithm is now:

  • Is the growth size less than 1/8 the size of the log?
  • Yes: create 1 new VLF equal to the growth size
  • No: use the formula above

So on SQL Server 2014, if you created your log at 1GB and it auto-grow in chunks of 512 MB to 200 GB, you’d have:

  • 16 VLFs from the initial log creation
  • All growths up to the log being 4.5 GB would use the formula, so growths at 1, 1.5, 2, 2.5, 3, 3.5, 4 GB would each add 8 VLFs * = 56 VLFs
  • All growths over 4 GB will only create 1 VLF per growth = (200 – 4) x 2 = 392 VLFs
  • Total = 392 + 56 + 16 = 464 VLFs

464 is a much more reasonable number of VLFs than 3200, and will be far less of a performance problem.