Using Mount Points in a Microsoft SQL Cluster Server Environment

When we use an Cluster for supporting SQL Instances in medium or bigger organizations we will have some TeraByte of data. Our Infra-Structure must be prepared to grow and in some times to grow faster without the possibility of stopping to improve or migrate, so there are some Advantages of using the NTFS volume mount points feature in a Microsoft Cluster Server Environment, such as:

1 – With the NTFS volume mount points feature, you can surpass the 26-drive-letter limitation.

a) As Example, In a Infra-structure of a 4 Node Cluster, with Multiple SQL instances, we easily reach the limit of the 26 Drive letter, if mount points are not used. With mount points feature you almost don’t have limit. read more about limits here to 2003 and here to 2008  To resume: Windows Server products support up to 8 buses per adapter, 128 target IDs per bus, 255 LUNs per target ID.

2 – With the NTFS volume mount points feature, you can implement smaller LUNS to the same Total Space, that will allow you to speed up your systems in very different situations, such as:

a) Backups will be faster because the number of files per LUN is smaller, and also because in case of SQL, data files also will be smaller.

b) Smaller Luns have better performance, and for some products like SQL is advised to split the number of data files, log files and tempdb files to increase performance.

3 – With the NTFS volume mount points feature, you easily can increment the space that an determinate SQL instance is using, without stopping and interferences with the normal availability of the System. You can On-line add a disk, and also on-line configure SQL data files location.

In some Backup tools is necessary to flag the device as an mount point to avoid problems: check this link here.

Don’t forget that you have multiple tempdb files (one per CPU core), in this case you must check this Link:

It is adviseble to split into multiple data files your data, create files with 30 GB maximum. : read more about here.:

It is adviseble to have separeted LUNs to DATA, TEMPDB, and LOG files, read more here:

You can read about adding mount points here

Hope that this information can be useful, thank you for comment and to rate this article.


About rodvars
Been working in IT Services/Consulting for the past 15 years. My main areas of work are planning, development, managing and administration System infrastructures focusing on optimizing user processes, enforcing business security, performance enhancements, high availabilty and infrastucture scalability.

2 Responses to Using Mount Points in a Microsoft SQL Cluster Server Environment

  1. spinglo blog says:

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  2. John Walker says:

    Thanks for sharing this informative article with us, to know more about Mount Point and the advantages of using mount point in SQL Server, visit:

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