ZFS Adaptive Replacement Cache (ARC) tends to use up to 75% of the installed physical memory on servers with 4GB or less and upto everything except 1GB of memory on servers with more than 4GB of memory to cache data in a bid to improve performance.

This can significantly affect performance on mission critical servers running Databases etc.

To identify how much memory uses:

# kstat -m zfs | grep size
 
        data_size                       18935877120
        hdr_size                        66041496
        l2_hdr_size                     0
        l2_size                         0
        other_size                      11310112
        size                            19013228728

Here “19013228728” (approx 18G) indicates the total memory used by ZFS.

Alternatively, the following mdb command show ZFS ARC usage:

# echo "::arc" | mdb -k|grep size
size                      =      2048 MB
hdr_size                  =  12493584
data_size                 = 2048608256
other_size                =  86475456
l2_size                   =         0
l2_hdr_size               =         0

It makes sense to cap the maximum ZFS ARC can use on servers where memory requirement for other services is more memory.

To set the maximum limit for ZFS ARC, edit /etc/system file and add the following line

set zfs:zfs_arc_max=2147483648

where 2147483648 restricts the usage to a maximum of 2GB physical memory. Unfortunately, this requires a reboot for the setting to take effect and cannot be dynamically changed.

Attach a Block Device

sunsolaris# lofiadm -a /export/software/iso_image.iso

/dev/lofi/1

Mount the ISO Image block device

sunsolaris# mount -F hsfs -o ro /dev/lofi/1 /mnt

Mount the mounted ISO image to the Guest zone

sunsolaris# mount -F lofs /mnt /zones/myzone/root/mnt

Where /zones/myzone/root is the root of the Zone. The files should now be visible under /mnt on the guest zone.

dladm is the admin utility for Data-Link Interface which helps to display informarthe like Link Status (UP/DOWN), Speed, Duplex, MTU, VLAN Tagged and crucially statistics of network traffic on each of the interfaces historically as well as in real time. dladm can also configure and admin Link Aggregation on multiple NICs which we will not focus here.

Show Link Status/Speed/Duplex

# dladm show-dev
nxge0           link: down      speed: 0     Mbps       duplex: unknown
nxge1           link: down      speed: 0     Mbps       duplex: unknown
nxge2           link: up        speed: 1000  Mbps       duplex: full
nxge3           link: up        speed: 1000  Mbps       duplex: full

As you can see above the “show-dev” option lists all the network interfaces with Link Status (UP/DOWN), current speed in Mbps and Duplex (Half/Full)

Show Link Status

# dladm show-link
nxge0           type: non-vlan  mtu: 1500       device: nxge0
nxge1           type: non-vlan  mtu: 1500       device: nxge1
nxge2           type: non-vlan  mtu: 1500       device: nxge2
nxge3           type: non-vlan  mtu: 1500       device: nxge3

Here “show-link” option reveals the MTU and the VLAN tagging detail on each of the interfaces on the system.

Show Stats of all Interfaces for all time

# dladm show-dev -s
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0
nxge1           0         0           0       0         0           0
nxge2           179625752557169463759657      581104982 3964684165410
nxge3           22240891  1834257868  0       5198483   395084708   0

The “-s” option along with “show-dev” or “show-link” displays network traffic statistics including Input/Output packets, input/output errors.

Stats in real-time

To show the stats of a particular interface in real-time use the “-i” option which is the interval in seconds. The first line shows again historic stats and later on the real-time information for every “n” seconds (5 seconds in our example)

# dladm show-link -s -i 5 nxge2
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           179637824757173944575957      581119516 3964706801670
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           961       319105             0       150       17874       0
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           887       263850             0       117       16505       0

If we fail to mention the interface then it takes the default interface (1st in the list). As you can see from the example below, we see stats for nxge0 which is not connected.

# dladm show-link -s -i 5
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0

The PCP script works on Solaris 10/9/8 and can be downloaded from here. Simply save the pcp.txt file to your Solaris Server as a Shell scripts (say pcp.sh) and change permissions to execute.

# chmod 755 pcp.sh

PIDs for TCP Port

Run PCP with “-p” option to show the PIDs of processes having a TCP port (say Port 22)

For instance, to find PIDs opening TCP port 22.

TCP Ports open by PIDs

Run PCP with “-P” option to show the TCP ports open by specific PID

For instance, here I try to find the TCP ports open by PID 18805

All PIDs for all open TCP Ports

Use the “-a” option to list all TCP ports open with all the PIDs

In Solaris 10, IP Forwarding can be enabled or disabled using the routeadm & ifconfig commands as against the ndd commands in Solaris 9 and earlier. The advantage is the change dynamic and real-time and the change persist across reboot unlike the ndd command.

Enable/Disable IP Forwarding globally 

To globally enable IP Forwarding in Solaris 10 use the routeadm command as follows:

In IPv4

solaris10# routeadm -e ipv4-forwarding

In IPv6

solaris10# routeadm -e ipv6-forwarding

The switches “-e” enables IP Forwarding.

To disable IP Forwarding

In IPv4

solaris10# routeadm -d ipv4-forwarding

In IPv6

solaris10# routeadm -d ipv6-forwarding

The switches “-d” enables IP Forwarding.

After the change run the following command for the changes to take effect.

solaris10# routeadm -u

Enable/Disable IP Forwarding per interface 

To enable IP Forwarding on a specific interface (say ce0) using the ifconfig command

In IPv4

solaris10# ifconfig ce0 router

In IPv6

solaris10# ifconfig ce0 inet6 router

To disable IP Forwarding for an interface (say ce0)

In IPv4

solaris10# ifconfig ce0 -router

In IPv6

solaris10# ifconfig ce0 inet6 -router

Adding or editing the IP address on a Solaris 10 server is different from the previous versions of the OS (Solaris 9, Solaris 8 etc).

In the previous versions of the Solaris Operating System, you need to edit the /etc/hosts file and add/edit the entry for the IP address and the hostname.

Example:

192.168.1.1   sun1

However, in Solaris 10, you should edit the /etc/hosts file (a symlink to /etc/inet/hosts file) and the  /etc/inet/ipnodes file and add an entry for IP address and hostname.

Once done, restart the Network service using

# svcadm restart network/physical

or reboot the server for the changes to take effect.

Although, the /etc/inet/ipnodes files is primarily for IPv6 only, without adding an entry to the file, the IP address (IPv4) doesn’t become active. This seems to be a known problem but the good news is this is now fixed in the Solaris 10 U4 (08/07 build).

Also, ensure that the /etc/netmasks file with the network ID and the netmask.