Disk Manufacturing & Screening Module (DMM) – File Server Test

The File Server Test is a great test for mixing writes and reads, for mixing transfer lengths, and mixing where the I/O accesses are.

Let’s go over each of these three attributes of the File Server Test.

Mixing of Writes and Reads:  The default for the File Server Test is to issue 20% Writes to the drive, and 80% Reads to the drive.  But you can modify this ratio by going to the Advanced Options dialog and inputting the desired Write/Read I/O Ratio.  In the picture below, we have entered “75” – this means we want 75% of the I/O to be Writes (and 25% to be Reads).

Mixing of Transfer Lengths: The File Server test will randomly pick transfer lengths between 8 and 128.  You can modify this behavior by going to the “Fixed/Random Transfer Length” section, selecting the “Random” radio button, and inputting any value larger than 8.  In the picture below, we have entered the number 32.  This means this File Server Test will randomly pick transfer lengths between 8 and 32.

Mixing of Accesses to the Drive: The File Server Test accesses the drive in a random fashion (so, in particular, it is NOT a sequential access test).

In summary, the File Server Test is the perfect test for mixing up all the normal parameters like Writes & Reads, transfer lengths, and accesses to the drive.