kern/113098: Cannot read from amrd while under heavy load

[Michael]

>Number:         113098
>Category:       kern
>Synopsis:       Cannot read from amrd while under heavy load
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 28 18:50:02 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     Michael
>Release:        6.2-release
>Organization:
>Environment:
FreeBSD jailserver 6.2-RELEASE-p5 FreeBSD 6.2-RELEASE-p5 #0: Sat May 26 06:19:58 PDT 2007     root at jailserver:/usr/obj/usr/src/sys/SMP amd64
>Description:
When I put a heavy load on the array, I can't do any kind of reads from it until the process finishes.
>How-To-Repeat:
A small perl script I wrote to do it (my array is mounted on /mnt/test1):

#!/usr/bin/perl

my $i = 0;
while ($i <= 100) {
system("dd if=/dev/zero of=/mnt/test1/ddfile-" . $i . " bs=1m count=100 &\n");
$i++;
}

While this script is running, I can't do anything that reads the array. The only thing I can do is watch gstat and see that it's getting data written to it.

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: