13 November 2010

Host Info - Memory

This post on memory is the first in a series on how to retrieve various
bits of host information from Solaris, Linux, and FreeBSD.  The OS
details are:

        HOSTS:          snorkle (sunhost), tux (linhost), beastie (bsdhost)
        PROMPT:         host [0]
        Solaris INFO:   Solaris 10, x86
        Linux INFO:     CentOS 5.4, x86
        FreeBSD INFO:   FreeBSD 8.1, x86

Of note, most of the following is applicable to previous OS releases,
though I've tried to note alternatives when necessary for older OS
versions.  Moving on to details, for memory we must consider both swap
space and physical memory.  To obtain both in Solaris:

        snorkle [0] /usr/sbin/swap -l
        swapfile             dev  swaplo blocks   free
        /dev/dsk/c1t0d0s1   32,1       8 2313352 2313352

    Assuming the default 512 byte block size, to get the size in GB
    (1.10 GB), use 'bc':

        snorkle [0] echo "scale=2 ; (2313352 / 2) / 1048576" | /usr/bin/bc
        1.10

        sunhost [0] /usr/platform/`/usr/bin/uname -i`/sbin/prtdiag -v | /usr/bin/grep ^Memory
        Memory size: 2048 Megabytes

    For some Solaris hosts, 'prtdiag' doesn't give up much or any
    information, such as on my test instance which is a VM (virtual
    machine) in VirtualBox.  This may be the case in other VM software
    as well as on some Solaris x86 hosts.  When 'prtdiag' doesn't provide
    anything useful, go with 'prtconf':

        snorkle [0] /usr/sbin/prtconf | /usr/bin/grep ^Memory
        Memory size: 1024 Megabytes

In Linux:

        tux [0] /bin/egrep 'MemTotal:|SwapTotal:' /proc/meminfo
        MemTotal:      1035140 kB
        SwapTotal:     1052248 kB

    If you want to see what devices are providing the swap space (size
    is listed in KB, so divide by 1048576 to get GB):
        tux [0] /sbin/swapon -s
        Filename                                Type            Size    Used    Priority
        /dev/sda3                               partition       1052248 0       -1
        tux [0] /bin/cat /proc/swaps
        Filename                                Type            Size    Used    Priority
        /dev/sda3                               partition       1052248 0       -1
In FreeBSD:
        beastie [0] /usr/sbin/swapinfo
        Device          1K-blocks     Used    Avail Capacity
        /dev/mirror/gm0s1b   1048576        0  1048576     0%
    'swapinfo' reports in KB, thus for MB, divide by 1024, for GB,     divide by 1048576:
        beastie [0] echo "scale=2; 1048576 / 1024" | /usr/bin/bc
        1024.00

        beastie [0] /sbin/sysctl hw.realmem
        hw.realmem: 1073676288
    'hw.realmem' is the memory available to FreeBSD reported in bytes, as     opposed to 'hw.physmem' which is the total reporting physical memory.     To get MB, divide by 1048576, GB, divide by     1073741824:
        beastie [0] echo "scale=2; 1073676288 / 1048576" | /usr/bin/bc
        1023.93
Still to come in the series, CPUs.

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