Saving data

Health Center can save the data that it is currently analyzing to a number of .hcd files on the hard disk. The number of files that Health Center creates depends on the length of time that you have been monitoring the application, and the number of backing files that you chose to keep. You can open the files in Health Center at a later date, without the need for a live connection.

While Health Center is monitoring an application, it stores data in temporary backing files. Each file can be up to 2.5 GB in size, which is the maximum amount of data that you can open in Health Center at any one time. When a backing file reaches 2.5 GB, a new backing file is created, until Health Center reaches the maximum number of files. This number is 5 by default, which should be sufficient for several days of monitored data. You can change this value by clicking File > Preferences... > IBM® Monitoring and Diagnostic Tools - Health Center > Data Storage Settings, then changing Number of backing files to keep. When the number of backing files reaches this value, and the last file reaches 2.5 GB, the first file is discarded and a new file is created. When you close Health Center, all the backing files are discarded, unless you save them.

To save the backing files, select File > Save Data..., enter or browse for the directory in which to save the files, then specify a file name. When the files are saved, the file names have the following format: 
  filename_yyyymmddhhmm_n.hcd
where filename is the file name that you specified, yyyymmddhhmm is a date and time stamp, and n is a number which starts at 1 and increments when a new file is created.

You can open the files in Health Center at a later date. You do not need use the same Health Center instance that created the files; you can pass the files to another instance of the same version, for analysis. For more information, see Loading saved data.

Notes:
  • The backing files work independently from the storage of data in memory when you view the data through the user interface.
  • All available data is saved. If you cropped the displayed data by dragging to select only a particular time interval, the cropping settings are lost when you later open the saved file. If you enabled Sliding window truncation, data outside the sliding window that you selected is saved, if the data has not yet been removed from the disk. The saved data is available when you later open the file.
  • For IBM SDK, Java™ Technology Edition, Version 5 service refresh 9 and earlier, and Version 6 service refresh 4 and earlier, the Health Center agent also stores data to disk, in the perfmon.out file in the temporary directory of your operating system. This data is a result of temporary buffering, and should not be used for analysis because it is not complete.