Turn off savecore? (How many dumps will you need?)

Once an image of a system crash has been captured, you need to again assess how you are doing on disk space. Do you have room for a subsequent set of savecore files should the system crash again? If not, you might want to move the files to another file system for analysis, clearing up space for the next crash. If you don't plan to analyze the files yourself, archive them to tape as soon as possible and free up the disk space.

At this time, the second question you need to ask yourself is whether you really need another set of postmortem files? To answer this, you need to consider the recent history of the system's performance. Has it been crashing a lot lately and you've just enabled savecore to capture one crash? Have the symptoms of the past crashes been reliably predictable?

For example, if your system crashes only when you boot a certain kernel, you probably only need the one set of savecore files and can disable savecore for the time being. If, however, your system has never crashed before, it would be wise to keep savecore enabled for now. It is often a good idea to have at least two or more sets of crashes for comparison.

Generally speaking, we feel savecore should always be enabled and ready to go in case the worst happens and your system decides to panic.

If you choose to maintain the savecore files on disk, use the UNIX compress command to squeeze them down to a smaller size . This will gain you some disk space. If you've never used compress before, here's an example that might convince you of its worth. The following savecore files are from a large Sun SPARCcenter 2000 server.

Figure 4-1 Compress your savecore files to save disk space

 Hiya...  ls -l  total 268154  -rw-rw-rw-  1 kbrown   15       1272308 Sep  1 12:28 unix.0  -rw-rw-rw-  1 kbrown   15     135077888 Sep  1 12:29 vmcore.0  Hiya...  compress unix.0 vmcore.0  Hiya...  ls -l  total 51082  -rw-rw-rw-  1 kbrown   15        669336 Sep  1 12:28 unix.0.Z  -rw-rw-rw-  1 kbrown   15      24592643 Sep  1 12:29 vmcore.0.Z  Hiya... 

The 135-megabyte vmcore.0 file compressed to less than 25 megabytes ” a huge saving!