The Performance Monitoring Archive (PMA)

Hopper OST disk space in use

When you first visit this page you get scratch file system OST use with "scratch" on the left and "scratch2" on the right . The selection boxes will let you customize which two graphs you want to look at. For example, you could have the scratch OST0000 on the left and scratch OST0001 on the right.

Each graph gives the details for one OST and compares it to the average for that file system. The blue line tracks how many GB of space were occupied on that OST at a particular moment for each day since the file systems were reformatted in April. The red line gives the average for all OSTs on that file system as well as the standard deviation (errorbars). Thus the OST0000 graph, which is displayed by default when you first visit the page, is the one that shows the significant imbalance on both file systems over time. Other graphs will all have the blue line almost entirely enclosed within the red.

hopper_scratch 0000 hopper_scratch2 0000

notes on the graphs


  • 1. I've artificially scaled the graphs to a maximum of 4TB per OST, but I don't actually know if that is the correct figure - it seems pretty close.
  • 2. I don't include OST0000 in the average and standard deviation calculation in the currently displayed graphs. I decided to leave it out because it is that OST's departure from otherwise "average" behavior we wanted to examine.
  • 3. The data sample is taken at 00:00:00 (Midight) each day if that sample is available. Otherwise, no data is recorded for that day.