requests for mbufs denied increasing

[Alexandre Biancalana]

Hi list,
   
    I've a NFS/FTP server used as backup server, receiving few 
connections with high volume of data (100GB/Day). During this period the 
"requests for mbufs denied (mbufs/clusters/mbuf+clusters)" of netstat -m 
is increasing constantly, now is:

151/404/555 mbufs in use (current/cache/total)
65/141/206/65456 mbuf clusters in use (current/cache/total/max)
65/79 mbuf+clusters out of packet secondary zone in use (current/cache)
0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
167K/383K/550K bytes allocated to network (current/cache/total)
9053239/2872380/2872048 requests for mbufs denied 
(mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/5/4432 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
2220 calls to protocol drain routines

    I tried to increase the kern.ipc.nmbclusters from 16192 to 32728 and 
65456, without success. Before increase this I'he to boot the machine 
because this stopped to accept new network connections and a simple ping 
returned "sendto: *No buffer* space available".

    The machine is running 6.1-STABLE updated yesterday, is a P4 3Ghz HT 
enabled, 512MB Ram, 4 IDE 200GB discs and 4 SCSI 73GB, all of then are 
striped with geom_stripe, building an 1 TB volume used to store all 
backup data.

  top output:
last pid:  3350;  load averages:  0.96,  0.87,  
0.78                          up 0+00:50:25  10:21:39
60 processes:  2 running, 58 sleeping
CPU states: 27.3% user,  0.0% nice,  7.1% system,  0.4% interrupt, 65.2% 
idle
Mem: 151M Active, 147M Inact, 155M Wired, 27M Cache, 59M Buf, 968K Free
Swap: 512M Total, 224K Used, 512M Free, 4K In

vmstat 5 output:
 procs      memory      page                    disks     faults      cpu
 r b w     avm    fre  flt  re  pi  po  fr  sr ad0 ad1   in   sy  cs us 
sy id
 1 4 1  458640  26264  136   8   1   0 3073 2879   0   0 8045 7062 19992 
19 11 71
 1 4 0  458668  21048    2  23   0   0 3680 3438  34  42 1153 3082 4492 
40  6 54
 0 5 0  458696  18648    2   4   0   1 3551 3414  34  37 1144 3524 5274 
33  5 62
 1 4 0  458724  23492   64   5   5   0 3266 3426  60  51 1253 2125 4234 
28  5 67


 Best Regards,

Alexandre