Category: File System

File System

Steps needed to create LUNs and to make them accessible by windows ISCSI initiators.

Steps needed to create LUNs and to make them accessible by windows ISCSI initiators.

Steps needed to create LUN and to make accessible by windows ISCSI initiators.

  • mohit_netapp02*> lun setup

This setup will take you through the steps needed to create LUNs
and to make them accessible by initiators. You can type ^C (Control-C)
at any time to abort the setup and no unconfirmed changes will be made
to the system.

  • Do you want to create a LUN? [y]: y
  • Multiprotocol type of LUN (solaris/windows/hpux/aix/linux/netware/vmware/windows_gpt)[linux]: windows

A LUN path must be absolute. A LUN can only reside in a volume or
qtree root. For example, to create a LUN with name “lun0” in the
qtree root /vol/vol1/q0, specify the path as “/vol/vol1/q0/lun0”.

  • Enter LUN path: /vol/test_vol/test_lun0

A LUN can be created with or without space reservations being enabled.
Space reservation guarantees that data writes to that LUN will never

  • Do you want the LUN to be space reserved? [y]: Object action: admin.util.true

Size for a LUN is specified in bytes. You can use single-character
multiplier suffixes: b(sectors), k(KB), m(MB), g(GB) or t(TB).

  • Enter LUN size: 55g

You can add a comment string to describe the contents of the LUN.
Please type a string (without quotes), or hit ENTER if you don’t
want to supply a comment.

  • Enter comment string:

The LUN will be accessible to an initiator group. You can use an
existing group name, or supply a new name to create a new initiator
group. Enter ‘?’ to see existing initiator group names.

  • Name of initiator group [windows]: Test_windows

Type of initiator group Test_windows (FCP/iSCSI) [iSCSI]: iSCSI
An iSCSI initiator group is a collection of initiator node names.Each
node name can begin with either ‘eui.’ or ‘iqn.’ and should be in the
following formats: eui.{EUI-64 address} or iqn.yyyy-mm.{reversed domain
name}:{optional string composed of alphanumeric characters, ‘-‘, ‘.’
and ‘:’}
Eg: or eui.02004567A425678D
You can separate node names by commas. Enter ‘?’ to display a list of
connected initiators. Hit ENTER when you are done adding node names to
this group.

  • Enter comma separated nodenames: ?

Initiators connected on adapter ism_sw1:
iSCSI Initiator Name                  Group   windows   windows
Enter comma separated nodenames:
Enter comma separated nodenames:
The initiator group has an associated OS type. The following are
currently supported: solaris, windows, hpux, aix, linux, netware
or vmware.

  • OS type of initiator group “Test_windows” [windows]: windows

The LUN will be accessible to all the initiators in the
initiator group. Enter ‘?’ to display LUNs already in use
by one or more initiators in group “Test_windows”.

  • LUN ID at which initiator group “Test_windows” sees “/vol/test_vol/test_lun0” [0]: 1

LUN 1 is already mapped to by initiator
in group windows
LUN ID at which initiator group “Test_windows” sees “/vol/test_vol/test_lun0” [0]: 2
LUN Path                : /vol/test_vol/test_lun0
OS Type                 : windows
Size                    : 55.0g (59057510400)
Initiator Group         : Test_windows
Initiator Group Type    : iSCSI
Initiator Group Members :
Mapped to LUN-ID        : 2

  • Do you want to accept this configuration? [y]: y
  • Do you want to create another LUN? [n]: n
  • mohit_netapp02*> lun showq

lun: unrecognized command “showq”
The following commands are available; for more information
type “lun help <command>”
aluadb              destroy             move                set
attribute           df                  offline             setup
clone               geometry            online              share
comment             help                rescan              show
config              hist                resize              snap
config_check        map                 select              stats
create              maxsize             serial              unmap

  • mohit_netapp02*> lun show

/vol/bod_iscsi/asm1            5g (5368709120)    (r/w, online, mapped)
/vol/mohitsnap/lun0         502.0g (539019048960)  (r/w, online, mapped)
/vol/test_vol/test_lun0     55.0g (59057510400)   (r/w, online, mapped)



Maximum LUN resize limits on NetApp

Be aware there are some limits to resize the Netapp size. Due to the geometry of the LUN at the time it was created it can only be resized to a maximum of ~10 times the original size of the LUN.

One way to see this is at the command line, for the command to be available you need to run ‘priv set diag‘ and then you will have access to the ‘lun geometry‘ command. From there you can see the LUN size as well as the maximum LUN size that is available.


Here is a table of some of the results:

LUN Size Maximum Resize
< 50g 502g
51-100g 1004g
101-150g 1506g
151-200g 2008g
201-251g 2510g
252-301g 3012g
302-351g 3514g
352-401g 4016g


Benchmarking for System and High Memory-CPU utilization – Part 1

Benchmarking for System and High Memory-CPU utilization – Part 1

Hello Guy’s,

Every System Admin and technical person who is working or doing any kind of High Availability stuff, He really needs bench marking to check and verify system health under development, here I am very beginner in this kind of system benchmarking to know how server/CPU/memory and network reacts when doing this and given load (purposely) on system to use or run the service or process. I will explain how I have done this in the part -2 😉

Memory Util


CPU Util



oprofile a system wide profiler

oprofile a system wide profiler

** What is oprofile

In short “oprofile is a system-wide profiler”
need to profile an application and its shared libraries, examine hardware effects such as cache misses and capture the performance behaviour of entire system, then surely you need go with oprofile.

There is to many options and conditions spcefied, where we use only simple and easy one for further details, Please Read Man Pages 😉

Many CPUs provide “performance counters”, hardware registers that can count “events”; for example, cache misses, or CPU cycles. OProfile provides profiles of code based on the number of these occurring events: repeatedly, every time a certain (configurable) number of events has occurred, the PC value is recorded. This information is aggregated into profiles for each binary image.

Some hardware setups do not allow OProfile to use performance counters: in these cases, no events are available, and OProfile operates in timer/RTC mode

** All Docs, Examples and Bugs you will find @

# download tar from or you can install it using yum also

[ ~]# yum install oprofile

Before you can use OProfile, you must set it up. The minimum setup required for this is to tell OProfile where the vmlinux file corresponding to the running kernel is, for example :

[ ~]#  opcontrol –vmlinux=/boot/vmlinux-`uname -r`

If you don’t want to profile the kernel itself, you can tell OProfile you don’t have a vmlinux file :

[ ~]# opcontrol –no-vmlinux

Here we used –no-vmlinux and specified other session directory than default location (/var/lib/oprofile)

[ ~]# opcontrol –no-vmlinux –session-dir=/home/prod/tmpsession

Now we are ready to start the daemon (oprofiled) which collects the profile data :

[ ~]# opcontrol –start –session-dir=/home/prod/tmpsession
Using default event: GLOBAL_POWER_EVENTS:100000:1:1:1
Using 2.6+ OProfile kernel interface.
Using log file /home/prod/tmpsession/samples/oprofiled.log
Daemon started.
Profiler running.

When I want to stop profiling, I can do so with :
(Here I have ran opcontrol only 1 min)
[ ~]# opcontrol –shutdown
Stopping profiling.
Killing daemon.

Lets see what your system & apps tell you 🙂
ophelp : This utility lists the available events and short descriptions.

[ ~]# opreport –session-dir=/home/prod/tmpsession
CPU: P4 / Xeon with 2 hyper-threads, speed 2992.73 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000
samples|      %|
1109031 51.2560 no-vmlinux
479089 22.1420
207263  9.5791
97973  4.5280
91993  4.2516 nagios
35979  1.6628 php
35765  1.6529
25203  1.1648
21412  0.9896 mysqld
11566  0.5345
10008  0.4625 oprofiled
7661  0.3541
6736  0.3113
5698  0.2633
4488  0.2074 rateup
3500  0.1618
2138  0.0988 bash
1556  0.0719
1234  0.0570
606  0.0280
328  0.0152
316  0.0146
290  0.0134 atop
272  0.0126 sendmail.sendmail
243  0.0112 grep
176  0.0081 nscd
172  0.0079 ping
153  0.0071 nebmodBY0Y2I (deleted)
144  0.0067
121  0.0056 init
106  0.0049 gawk

with using symbols you can simply find which apps supporting module takes high load
[ ~]#  opreport –exclude-dependent –symbols –long-filenames –session-dir=/home/prod/tmpsession
CPU: P4 / Xeon with 2 hyper-threads, speed 2992.73 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000
samples  %        app name                 symbol name
1109031  51.2560  /no-vmlinux              /no-vmlinux
209506    9.6827  /lib64/       _int_free
207263    9.5791  /usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi/CORE/ /usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi/CORE/
97973     4.5280  /usr/lib64/ /usr/lib64/
91993     4.2516  /usr/local/nagios/bin/nagios /usr/local/nagios/bin/nagios
44574     2.0601  /lib64/       free
35765     1.6529  /usr/lib64/ /usr/lib64/
35032     1.6191  /lib64/       vfprintf
22061     1.0196  /lib64/       _IO_vfscanf
21412     0.9896  /usr/libexec/mysqld      /usr/libexec/mysqld
16883     0.7803  /lib64/       _int_malloc
13631     0.6300  /lib64/       memcpy
13165     0.6084  /lib64/       _IO_file_xsputn@@GLIBC_2.2.5
1560      0.0721  /lib64/         _dl_relocate_object
1462      0.0676  /usr/bin/php             lstep
1385      0.0640  /usr/bin/php             zend_do_fcall_common_helper_SPEC
1258      0.0581  /lib64/       rawmemchr
1234      0.0570  /usr/lib64/mysql/ /usr/lib64/mysql/
1226      0.0567  /lib64/       realloc
1180      0.0545  /lib64/       __tzfile_compute
1156      0.0534  /lib64/         check_match.8509
1146      0.0530  /usr/bin/php             _zend_mm_free_int
1084      0.0501  /usr/bin/php             zend_hash_quick_find
1029      0.0476  /lib64/       __mpn_mul_1
747       0.0345  /lib64/       fgets
738       0.0341  /usr/bin/php             _zval_ptr_dtor