Determine available Drive Space

A useful undocumented extended stored procedure, xp_fixeddrives is used
to determine how much disk space is free. Its result set includes the
drive letter and the number of megabytes that are free for that drive. The
output can be inserted into a table and, if a date is established on a
table with the output from xp_fixeddrives, a trend can be identified. If a
trend is established with the decrease in disk space, users can anticipate
when more disk space will be needed. The key is to use the output from
xp_fixeddrives to do trending analysis for capacity management of the SQL
servers.

First, you need to qualify the execution of extended procedures with the
master database. The following code executes the extended stored
procedure and returns a list of the hard drives and the free space available for
each drive:

EXEC master..xp_fixeddrives

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