Building a QFS shared file system tutorial

This article provides the steps necessary to create a QFS Shared file system

Tutorial objectives:

  • Install, patch, and configure Sun QFS standalone
  • Learn what processes run in QFS standalone environment, compare to SAM-QFS
  • Learn shared filesystem concepts
  • Successfully create a shared SAN filesystem
  • Verify functionality
  • Learn server failover concepts
  • Successfully switch server and client roles between filesystem host
  • Unconfigure environment

For this tutorial, we will use pinky as the server, and perky as the client in the shared filesystem configuration. This document is not meant to replace any training, and will be very basic. It is the readers responsibility to have access to the installation and configuration guides for SAM-FS/QFS (either hard-copy or online from

In the interests of saving time, I am assuming that the SAM-QFS package and product patch have already been installed, but be aware of what package names are for SAM-FS vs QFS standalone.

Configuring shared filesystems

  1. Verify that both systems have visibility to the storage that will be used for the shared filesystem (in this tutorial I am using a Sun StorEdge T3+ array):
    s4u-sam# format
    Searching for disks...done
           0. c0t0d0 
           1. c1t40d0 
           2. c1t40d1 
           3. c1t40d2 
           4. c4t1d0 
           5. c4t1d1 
    Specify disk (enter its number):
    In this configuration, we will use c4t1d0 for metadata, and c4t1d1 for actual filesystem data. See SunQFS Filesystem Administrators Guide, page 5 for more information on metadata.
  2. Create a new file called LICENSE.4.0 in /etc/opt/SUNWsamfs/. Without this file, the daemons won't start and operations will fail.
    s4u-sam# cat /etc/opt/SUNWsamfs/LICENSE.4.0
  3. Configure the mcf file for the new filesystem.
    Note: The shared flag in the example below. See SunQFS Filesystem Administrators Guide, page. 42 for more information on configuring mcf file
    s4u-sam# cat /etc/opt/SUNWsamfs/mcf
    # Please verify these disk partitions are truly not in use
    samfs1                  20      ma      samfs1  -       shared
    /dev/dsk/c4t1d0s0       21      mm      samfs1  -       /dev/rdsk/c4t1d0s0
    /dev/dsk/c4t1d1s0       22      mr      samfs1  -       /dev/rdsk/c4t1d1s0
  4. Configure the hosts.familyname file for the QFS server. This file is responsible for defining the clients and servers that are allowerd to access the filesystem. See SunQFS Filesystem Administrators Guide, page 100 for more information on the hosts file
    s4u-sam# cat /etc/opt/SUNWsamfs/hosts.samfs1
    pinky    1       -         server      
    perky  2       -       
  5. Send a HUP signal to sam-fsd daemon on the server. This will make sam-fsd reread the configuration files.
  6. Run sammkfs to create the filesystem.
    s4u-sam# sammkfs -S samfs1
  7. Configure the services file for tcp communications between server and any clients. Add the following line to the /etc/inet/services file (note the port number- this will be used again later):
    samsock.samfs1  7105/tcp                        # QFS samfs1 port
    Send a HUP signal to inetd daemon to reread the services file.
  8. Verify that sam-sharefsd daemon is now running for this filesystem.
    s4u-sam# ps -ef | grep sam
        root  2046  2038  0 20:54:30 ?        0:00 sam-sharefsd samfs1
        root  2038     1  0 20:54:16 ?        0:00 /usr/lib/fs/samfs/sam-fsd
        root  3248  3182  0 13:15:17 pts/4    0:00 grep sam
  9. Create mount point for filesystem, and edit the /etc/vfstab file to add the new shared filesystem. The entry must have the shared option at the end of the line.
    samfs1  -       /samfs1 samfs   -       yes     shared,bg
  10. Mount the filesystem, either through mountall command, or mount it manually
    s4u-sam# mount samfs1 /samfs1
  11. The server is now ready to go. The steps will be the same on the client, specifying pinky as the filesystem server in the /etc/SUNWsamfs/hosts.samfs1 file.
  12. Once the client is configured, mount the filesystem on perky as well.
    s4u-sam# mount samfs1
    SAM-FS: Shared server is not responding
    SAM-FS: Shared server responded
  13. We now have successfully created a shared filesystem. You can verify the IP connection between the two hosts using netstat.
    s4u-sam# netstat -a | grep sam
    pinky.32850    perky.samsock.samfs1  24820      0 48632    0 ESTABLISHED
    30001761010 stream-ord 30001c25a18 00000000 /var/opt/SUNWsamfs/uds/Fsd

    Server Failover

    As long as both machines in this scenario are configured to communicate with the metadata device (both physical connectivity and through the mcf file), both machines are eligible to be servers for the filesystem.

    Live Failover (when server is up)

    On the metadata server, run the samsharefs command to define the new server.

    s4u-sam# samsharefs -s perky samfs1
    # Host file for family set 'samfs1'
    # Version: 3    Generation: 2    Count: 2 
    # Server = host 0/pinky, length = 80 
    # Pending Server = host 1/perky  

    Failover will take about 60 seconds. During this time, samsharefs commands won't come back, but eventually you'll see the new server established.

    Now on either machine we can see who the new server is.

    s4u-sam# samsharefs samfs1
    # Host file for family set 'samfs1'
    # Version: 3    Generation: 3    Count: 2 
    # Server = host 1/perky, length = 80
    pinky 1 - 
    perky 2 - server

    Server Failover when server is down

    Typically, if the metadata server is having issues, you'll want to have it either completely disconnected or powered off to ensure that it does not try to regain control.

    Issue an init 0 to whichever box has server access to the filesystem (use samsharefs command to determine this). Then, use the samsharefs command to force failover to one of the clients that can be used as an alternate server.

    s4u-sam# samsharefs -R -s perky samfs1
    # Host file for family set 'samfs1'
    # Version: 3    Generation: 4    Count: 2 
    # Server = host 1/perky, length = 80
    perky 2 - server
    pinky 1 -

    These steps are specific for QFS standalone. There are additional procedures for failover on SAM-QFS configurations. These steps are discussed in the Sun SAM-QFS File System Administrators Guide, page 125.

    When mounting the filesystem (manually or through vfstab), there are several shared filesystem specific options that can be used. These options are beyond the basic scope of this lab, but are worth knowing. These can be foind in the Sun SAM-QFS File System Administrators Guide page 132.