problem with nfs performane

[Alok Pandey]

Alok Pandey wrote:
> hi Guru's
> I am a new to linux and facing problem with nfs performance . Below is 
> the details:
>
> NFS SERVER details:
> os centos 4.3 final kernel(Linux 2.6.9-42.0.3.ELsmp)
> nfs-utils-1.0.6-70.EL4
> system-config-nfs-1.2.8-1
> nfs-utils-lib-1.0.6-3
> /home is exported
>
> RAM-4 GB
> Hardisk : 880G (hw raid5).
>
> NFS Client deltails:
> os centos 4.3 final kernel (2.6.9-34.EL)
> mount option default.
> Now the problem is:
> 1)- nfs is not performing well.(i.e r/w operation is very slow, it 
> almost hangs up ). whenever the average cpu load is 49%.
> 2) I am using NIS share automounter to mount the the nfs share to all 
> client with option soft,intr,rw. if i have to change it to something 
> like (hard, rw etc) do i need to restart the nfs server.??
> 3) nfs server is on the testing machine so the cpu will be overloaded 
> always.Is their any way around so that my nfs will remain unaffected.
>
> Below is the details of cpu loads at the time when nfs was struggling 
> with performance.:
>
> root# sar -u 2 5
> 04:26:48 PM       CPU     %user     %nice   %system   %iowait     %idle
> 04:26:50 PM       all     49.75      0.00      0.50      0.00     49.75
> 04:26:52 PM       all     49.87      0.00      0.25      1.50     48.37
> 04:26:54 PM       all     49.75      0.00      0.50      0.25     49.50
> 04:26:56 PM       all     49.75      0.00      0.25      0.00     50.00
> 04:26:58 PM       all     49.75      0.00      0.50      2.00     47.75
> Average:          all     49.77      0.00      0.40      0.75     49.07
>
> [root ~]# ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
> %CPU   PID USER     COMMAND
> 99.5 27920 1013     ./eib /home/rajeshsareen/Testing/data
> 0.0     9 root     [kacpid]
> 0.0  9950 root     smbd -D
> 0.0     8 root     [khelper]
> 0.0  8461 apache   /usr/sbin/httpd
> 0.0  8460 apache   /usr/sbin/httpd
> 0.0  8459 apache   /usr/sbin/httpd
> 0.0  8458 apache   /usr/sbin/httpd
> 0.0  8457 apache   /usr/sbin/httpd
>
> [root~]# iostat
> Linux 2.6.9-42.0.3.ELsmp (X)       03/07/2007
>
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>          14.84    0.00    0.78    0.60   83.78
>
> Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
> sda               2.03       192.63        97.31  114436264   57810512
> sda1              0.00         0.00         0.00        437        408
> sda2             35.94       192.63        94.89  114434843   56374872
> sdb               2.18       198.21       150.70  117753007   89529840
> sdb1              0.00         0.00         0.00       2747        408
> sdb2              7.12         5.69        51.28    3383110   30465176
> sdb3              0.27         0.23         1.95     134768    1157488
> sdb4              0.00         0.00         0.00          2          0
> sdb5             35.90       192.28        94.92  114231300   56388768
> sdc               2.14       198.36       150.15  117841314   89197840
> sdc1              7.10         5.57        51.26    3306228   30451272
> sdc2              0.27         0.23         1.94     133984    1150136
> sdc3             35.87       192.57        94.40  114400110   56078720
> sdd               2.15       198.87       149.91  118145314   89056672
> sdd1              7.11         5.68        51.23    3373812   30436328
> sdd2              0.27         0.22         1.94     131459    1154816
> sdd3             35.89       192.97        94.18  114639051   55947816
> md0               0.00         0.00         0.00       2922        408
> md1              34.16       679.08       245.09  403425258  145604104 
> # /home md3               0.49         0.23         3.73     134896    
> 2214952
> md2              12.83         9.93       101.82    5901698   60488032
>
> [root ~]# iostat -xtc 5 3
> Linux 2.6.9-42.0.3.ELsmp (traces)       03/07/2007
>
> Time: 05:13:05 PM
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>          14.85    0.00    0.78    0.60   83.77
>
> Time: 05:13:10 PM
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>          48.60    0.00    1.10    0.60   49.70
>
> Time: 05:13:15 PM
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>          48.95    0.00    1.20    0.00   49.85
>
>
> hopefully the above details are able to define the nfs problem. Plz 
> help me ?
>
> Thanks in advance
>
>
>
>