jw schultz wrote:
On Tue, Feb 17, 2004 at 06:47:19PM -0800, Marc Perkel wrote:It's on a dual xeon with 4 gigs of ram and a pair of 250 gig serial ata drives.
Actually - the problem is disk IO. And the disk IO is what makes the load levels go up. The load level is something that's readable can can be used to have rsync slow itself down. Nice doesn't do the trick. Nice helps - but even at nice +19 it still slows the system to a crawl when backing up from one drive to another.
Is that is on AIX with 12 AS400 CPUs or the VMS SSI cluster?
Or is that a single CPU linux box with a 2.4.?? kernel?
What happens is that the server is cooking along just fine serving about 2 million hits a day. Load level - according to top is running around 0.6 to 2.3 or so - and then rsync kicks in doing a backup between the drives and even though I'm running at nice +19 the load kicks up to around 50 and several services almost stop. That's why I'm asking for this feature.
So - if rsync could watch the load levels and pause every now and then to put a little space between disk access at high load levels it would make it a lot friendlier to the system. The reason nice doesn't work is that once the system call is made to access the disk - nice doesn't apply.
What load levels? Do you have some nice C code that can do that for ALL the platforms without misreading?
This is what process and i/o schedulers are for. Maybe you should contact the people responsible for whatever kernel it is you are running.
I'd rather get a response from real develpers than nay sayers telling me things that don't work. Its a real issue and it requires changes in rsync to make it work correctly.
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