My client autoinstallation/update hangs, crashes, or is ridiculously slow.

Goran Pocian reported an instance of unacceptable si_updateclient performance that went away when he upgraded from kernel 2.2.17 to 2.2.18.

He also noted that if you mount an NFS filesystem after executing si_prepareclient, si_getimage will retrieve its contents. As this can heavily increase network load, it can also cause bad performance.

Brian Finley reported other possible causes:

Every once in a while, someone reports some mysterious hanging or transfer interruption issue related to rsync. I had a chance to speak with Andrew Tridgell in person to discuss these issues.

We found two known issues that could be the source of these symptoms. One is a known kernel issue, and one is an rsync issue. The kernel issue is supposedly resolved in 2.4.x series kernels, (SystemImager has not yet been "officially" tested with 2.4.x kernels) and may not be present in all 2.2.x series kernels (I believe).

The rsync bug will be fixed in the rsync 2.4.7 release (to happen "Real Soon Now (TM)" ). The rsync bug is caused by excessive numbers of errors filling the error queue which causes a race condition. However, until rsync 2.4.7 has been out for some time, I will still recommend using v2.4.6 unless you specifically experience one of these issues.

Here's a hack that seems to work for Chris Black. Add "--bwlimit=10000" right after "rsync" in each rsync command in the <image>.master script.

	  Change: "rsync -av --numeric-ids $IMAGESERVER::web_server_image_v1/ /a/"
	  To:     "rsync --bwlimit=10000 -av --numeric-ids $IMAGESERVER::web_server_image_v1/ /a/"
	

Here are some tips on diagnosing the problem:

I hope this information helps...

A possible solution, suggested by Robert Berkowitz, is to add --bwlimit=10000 to the rsync options in the rsync initscript.