[Server-devel] Server-devel Digest, Vol 10, Issue 12

[Tony Pearson]

Wad,
Based on recommendations here:
http://www.ibm.com/developerworks/linux/library/l-tune-lamp-1/index.html?S_TACT=105AGX03&S_CMP=EDU

I suggest the following change to XS-150:

[root at schoolserver1 html]# cat /etc/sysctl.conf
# OLPC School server Kernel sysctl configuration file
#
# Forward packets
net.ipv4.ip_forward = 1

# Perform source route verification
net.ipv4.conf.default.rp_filter = 1

# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0

# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 1

# Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid = 1

# Controls the use of TCP syncookies
net.ipv4.tcp_syncookies = 1

# New parameters
net.ipv4.tcp_window_scaling = 1
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216

(this could be done during startup with "cat last-six-lines.txt >> 
/etc/sysctl.conf", we could fine-tune
these values later)

[root at schoolserver1 html]# cat /etc/fstab
LABEL=/1                /                       ext3    defaults,noatime 1 
1
LABEL=/boot             /boot                   ext3    defaults,noatime 1 
2
tmpfs                   /dev/shm                tmpfs   defaults        0 
0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 
0
sysfs                   /sys                    sysfs   defaults        0 
0
proc                    /proc                   proc    defaults        0 
0
/dev/VolGroup00/LogVol00 /library                ext3    defaults,noatime 
1 2
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 
0

(I added ",noatime" to first, second and seventh lines.  We might be able 
to use "sed" to make these changes, or just hard-code them.  Basically, if 
it has an "ext3" on it, add ",noatime" to the defaults.  "atime" is access 
time, so every time you read a file, it writes back the access time.  This 
is time consuming and probably not needed for our purposes.  Specifying 
",noatime" reduces the write load in a read-intensive configuration)

Thanks





Tony Pearson
Senior Storage Consultant, IBM System Storage?
Telephone: +1 520-799-4309 |  tie 321-4309 |  Cell: +1 520 990-8669
email: tpearson at us.ibm.com |  GSA: http://tucgsa.ibm.com/~tpearson
Blog: http://www.ibm.com/developerworks/blogs/page/InsideSystemStorage 
AKA: 990tony Paravane, eightbar specialist 


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