AIX snap - Prevent dump collection

You can specify the –Z flag with the AIX snap command to prevent it from collecting system dump data. The flag is not shown in the man page for snap. However, it is listed in the usage information.

# oslevel -s

7100-03-03-1415

# sysdumpdev -L

Device name:         /dev/lg_dumplv

Major device number: 10

Minor device number: 11

Size:                174708224 bytes

Uncompressed Size:   1131385360 bytes

Date/Time:           Tue Nov 11 12:56:15 2014

Dump status:         0

Type of dump:        fw-assisted

dump completed successfully

...

# man snap

snap Command

Purpose

       Gathers system configuration information.

Syntax

       snap [-@] [ -a ] [-z "product_name=prd_name,..." | "class=myclass,.." | ALL] [-M Timeout][ -A ] [ -b ] [ -B ] [ -c ] [ -C ] [ -D ] [ -f ] [ -F] [ -g ] [ -G ] [ -i ] [ -k ] [ -l ] [ -L ][

       -n ] [ -N ] [ -p ] [ -r ] [ -R  ] [ -s ] [ -S ] [ -t ] [ -T  Filename ] [ -w  ] [ -X ] [ -Y ][ -o OutputDevice ] [ -d Dir ] [ -v Component ] [ -O FileSplitSize ] [ -P Files ] [ script1

       script2 ... | All | file:filepath ]

       snap -e [ -m Nodelist ] [ -d Dir ]

       snap -z ADD ["product_name=prod_name" "class=myclass" "command_path=/tmp/myprod_myscript -a"]

       snap -z DELETE ["product_name=prod_name" ]

Description

       The snap command gathers system configuration information and compresses the information into a pax file. The file may then be written to a device such as tape or DVD, or transmitted to a

       remote system. The information gathered with the snap command might be required to identify and resolve system problems.

...

# snap

Usage: snap [-@gFGStnfkDpsAliIbBNLRwhHCZXYM] [ -z "product_name=productname, ..." | "class=classname, ..." | ALL ] [-o outputdevice] [-d dir] [All |

file:filename | scriptname1 [scriptname2] ...]

       snap [-aZ] [-o outputdevice] [-d dir]

       snap [-gGStnfkDpsAliIbBNLRwhHCZY] [-c] [-O splitsize] [-d dir] [All |

file:filename | scriptname1 [scriptname2] ...]

       snap [-o outputdevice] [-d dir]

       snap [-v component]

       snap [-c] [-O splitsize] [-d dir]

       snap [-r] [-d dir]

       snap [-gGS ]

       snap [-gG ]

       snap [-gh ]

       snap [-gS ]

       snap [ -HC | -P files ]

       snap [-g] [-T trcfile]

       snap [-T trcfile]

       snap [All]

       snap [file:filename]

       snap [scriptname1 [scriptname2] ...]

       snap [-e [-m nodenamelist]]

                 snap [ -z ADD "product_name=productname" "class=classname" "command_path=Absolutepathofyourdebugcommand" ]

                 snap [ -z DELETE "product_name=yourproductname" ]

                 snap [ -z "product_name=productname, ..." | "class=classname, ..." | ALL ]

                 snap [ -M snap_time_out_value ]

        -@ Gather workload partition information

        -a Gather all information.

        -g Gather general information.

        -T Captures a specific trace (specify full path name of the trcfile).

        -G Include Pd* ODM files in general information.

        -t Gather tcpip information.

        -n Gather nfs information.

        -f Gather file system information.

        -k Gather kernel information.

        -D Gather dump and /unix along with livedump information.

        -D -x Perform Automated Dump Analysis.

        -p Gather printer information.

        -s Gather sna information.

        -S Include security files in general information.

        -A Gather async (tty) information.

        -X Gather X.25 LPP information.

        -Y Gather IB Debug information.

        -i Gather Install information.

        -I Gather PCI-X-SCSI and SISSAS information.

        -l Gather programming language information.

        -b Gather SSA Adapter/Disk information.

        -B Skip SSA adapter dump collection when -b is specified.

        -R Gather SCSI RAID information.

        -L Gather logical volume manager (LVM) information.

        -N Suppress free space checking

        -w Gather workload manager (wlm) information.

        -H Gather general information without platform/scanout data.

        -C Gather just platform/scanout files.

        -P Gather just the specified platform/scanout files.

        -h Gather Hardware information.

        -e Gather HACMP information.

        -m node name list [separated by ,] to gather HACMP information.

        -c Create snap.pax.Z file.

        -o Send information to removable output device (/dev/rfd0).

        -d Directory to put information (/tmp/ibmsupt).

        -r Remove directory (/tmp/ibmsupt).

        -F Gather flash adapter related information.

        -v Output component snap file to stdout

            Current component choices are:

                 'async dump dump/autoload filesys general kernel lang printer XS25 sna tcpip install ssa scraid lvm wlm wpars hacmp pcixscsi sissas ctsupt products flash IB'

        -z To run third party debug commands

        -M To set the timeout for third party debug commands

           If, used with optoins other than -a/-z its value is ignored

        -Z Prevent dump collection.

If you run snap whilst a system dump has been recorded on the dump device (logical volume), then it will be collected and included in the snap data file. If there is a valid dump to collect you’ll see the message highlighted below in the snap output.

# snap -ac

Checking space requirement for general information.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. done.

Checking space requirement for tcpip information....................................................... done.

Checking space requirement for kernel information............... done.

Checking space requirement for printer information.... done.

Checking space requirement for dump information........

        Attention:  The dump is compressed, and we were not able to verify it is

        consistent with /unix.  Processing continues.

. done.

Checking space requirement for sna information.../var/sna not found

 done.

Checking space requirement for filesys information.................................. done.

Checking space requirement for async information................ done.

Checking space requirement for lang information.......... done.

...etc...

Gathering caa data

Gathering pcixscsi system information....... done.

Gathering sissas system information...... done.

Gathering IB system information..............................

Creating compressed pax file...

Starting pax/compress process... Please wait... done.

-rw-------    1 0        0         238702810 Nov 11 13:20 snap.pax.Z

The dump data is saved to /tmp/ibmsupt/dump, as shown below.

# cd /tmp/ibmsupt/dump

# ls -ltr

total 374408

-r-xr-xr-x    1 bin      bin         7975536 May 16 22:01 kdb_64

-rw-------    1 root     system         2118 Nov 11 12:57 minidump_last

-rw-------    1 root     system      8977113 Nov 11 13:19 unix.Z

-rw-------    1 root     system        13954 Nov 11 13:19 mdmprpt.out

lrwxrwxrwx    1 root     system            6 Nov 11 13:19 trcdead -> kdb_64

lrwxrwxrwx    1 root     system            6 Nov 11 13:19 livedumpdead -> kdb_64

lrwxrwxrwx    1 root     system            6 Nov 11 13:19 kdb -> kdb_64

lrwxrwxrwx    1 root     system            6 Nov 11 13:19 errdead -> kdb_64

-rw-------    1 root     system          784 Nov 11 13:19 dump.snap

-rw-------    1 root     system    174708224 Nov 11 13:19 dump.BZ

drwx------    2 root     system         4096 Nov 11 13:19 autoload

Specifying the –Z flag to snap prevents this data from being collected by snap.

# snap -aZc

Checking space requirement for general information............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. done.

Checking space requirement for tcpip information....................................................... done.

Checking space requirement for kernel information............... done.

Checking space requirement for printer information.... done.

Checking space requirement for dump information........ done.

Checking space requirement for sna information.../var/sna not found

 done.

Checking space requirement for filesys information.................................. done.

Checking space requirement for async information................ done.

Checking space requirement for lang information.......... done.

...etc...

Gathering caa data

Gathering pcixscsi system information....... done.

Gathering sissas system information...... done.

Gathering IB system information..............................

Creating compressed pax file...

Starting pax/compress process... Please wait... done.

-rw-------    1 0        0          42606819 Nov 11 13:29 snap.pax.Z

The snap file is much smaller without the system dump collection.

-rw-------    1 0        0   238702810 Nov 11 13:20 snap.pax.Z – includes dump info

-rw-------    1 0        0    42606819 Nov 11 13:29 snap.pax.Z – no dump info

If you are on a version of AIX that doesn’t have the snap –Z flag (such as AIX 5.3) then the alternative way to capture snap data without including the dump info is to run snap –a, when that is finished, remove the /tmp/ibmsupt/dump directory and run snap –c to create the snap pax file.

More information on snap and AIX system dumps:

http://www-01.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.cmds5/snap.htm?lang=en

https://www.ibm.com/developerworks/community/blogs/AIXDownUnder/entry/a_nice_clean_dump2?lang=en