On Tue, Jul 7, 2009 at 4:38 PM, Holger Parplies<wb...@parplies.de> wrote: > No, my point was, the "load average" is an attempt to fit the state of a > system into one single number (which, as we've agreed, is only good for > getting a quick impression, nothing more).
Exactly. On Linux systems (don't have enough high performance experience with other systems to say conclusively) the load average simply gives you a rough indication of the number of processes that are in the run queue. If you have one process running using 100% CPU, your load average will be 1. If you have one process running waiting 100% IO, your load average will be 1. To get a full picture you can run top (make sure if you have multiple CPUs you expand the display to show each one) or vmstat (I typically use `vmstat 1` to watch the data on 1 second intervals). vmstat has the benefit of splitting out the number of processing running on CPU and waiting on disk (see the first columns r and b) as well as showing you overall IO load and the type of CPU utilization. Here's a sample from vmstat of my desktop/server system running a local and remote backup at the same time: procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 2 2 0 35592 200332 1459116 0 0 73100 392 2884 2375 65 12 0 24 0 3 2 0 21508 200648 1473972 0 0 55036 0 2523 2641 28 6 4 63 0 2 1 0 24940 201092 1471664 0 0 81664 0 3085 2949 33 9 1 58 0 1 2 0 25512 201376 1472784 0 0 81216 1064 3094 2883 28 8 0 65 0 3 1 0 23612 201732 1475760 0 0 81256 0 3039 2939 28 8 1 64 0 Here we can see a pretty good mix of CPU and IO wait - Improving the capacity of either would lead to a reduction in backup times. -Dave ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
