IT Dribble

I had the task of rebuilding an Astaro UTM 220 with CentOS and the LCD panel looked so lifeless, So I decided to restore it to some version of functional! From my research I can see that the display is LCM-162 and utilises the lcd driver HD44780.

In a nut shell here is what I did:

• Download LCDproc (http://lcdproc.omnipotent.net/)
• Modify: lcdproc-0.5.6/server/drivers/hd44780-ext8bit.c

Change:

#define RS  STRB
#define RW  LF
#define EN1 INIT 

To:

#define RS  SEL
#define RW  INIT
#define EN1 LF 

• compile it with option: ‘./configure –enable-drivers=hd44780′
• make && make install
• Modify: /usr/local/etc/LCDd.conf

Change:

• Line 53: Driver=hd44780
• Line 502: ConnectionType=8bit
• Line 509: Device=/dev/parport0
• Line 544: Size=16×2

Test it:

LCDd -f -r 4 -c /usr/local/etc/LCDd.conf &

lcdproc -f -s localhost -p 13666 C M L

If it works its just a matter of copying: scripts/init-LCDd.rpm and scripts/init-lcdproc.rpm to /etc/init.d and configuring chkconfig properly.

Hopefully that helps.

For a raw filesystem try:

fdisk -l harddrive.img
mount -o ro,loop,offset=xxxxxxxxx harddrive.img /mnt/loop

or for filesystems with volume groups etc try:

losetup /dev/loop0 disk.img
kpartx -a /dev/loop0

Then to mount the first partition:

mount /dev/mapper/loop0p1 /mnt

Or to activate the volume group then mount the logical volume:

vgscan
vgchange -ay vg
mount /dev/vg/lv /mnt

Hope that helps.

I recently tried to copy a VMDK from ESXi version 6.0 to another server which was version 5.0 It failed the first time due to the virtual hardware being version 11, which isn’t supported on ESXi 5.0.
The next thing I tried, was to copy a VMDK across, that got added to the new virtual machine with no problems but when I attempted to boot the VM I received the following error:

An unexpected error was received from the ESX host while powering on VM vm-622.
Module DevicePowerOn power on failed. 
Unable to create virtual SCSI device for scsi0:1, '/vmfs/volumes/54813a47-8d0eedcc-43c8-001e0bd161d0/yubikey/Yubi-0.vmdk' 
Failed to open disk scsi0:1: Unsupported or invalid disk type 7.  Ensure that the disk has been imported.

I knew that it would be a problem and the solution was a simple one. Having recently migrated 40 KVM based VM’s to ESX, I was quite familiar with vmkfstools. To make the VMDK bootable perform the following:

vmkfstools -d zeroedthick -i server.INPUT.vmdk server.OUTPUT.vmdk

Then attach server.OUTPUT.vmdk as the new virtual harddrive.

Via the webconsole, click: Event, then read all the events, while taking note of them and actioning them as required.
Finally click: Clear All Events

So many times I need to measure the amount of IOPS on a Linux disk/storage system. While there are many tools for the jobs they just don’t seem to give you a ‘number’. For example Splunk indexers require 1200+ IOPS according to hardware recommendation guides but how do you find out if your any where close to that number? Use ‘bonnie++’, ‘iozone’ or perhaps ‘fio’? Well use any of those tools will create the type of read / write sequence you would like to replicate - but where the damn magic number???

Easiest two ways are:
Method #1:
run iozone -a (or bonnie++) in one screen then in another session / terminal use nmon, pressing D (capital D) to get disk stats and get the number from the Xfers column. This is your magic number (or IOPS reading)

┌nmon─14i─────────────────────Hostname=reddragon─────Refresh= 2secs ───19:51.57─
│ Disk I/O ──/proc/diskstats────mostly in KB/s─────Warning:contains duplicates─
│DiskName Busy    Read    Write       Xfers   Size  Peak%  Peak-RW    InFlight
│sda       99%    699.9     14.0KB/s  178.0   4.0KB  493%    3658.8KB/s   1   
│sda1       0%      0.0      0.0KB/s    0.0   0.0KB    0%       0.0KB/s   0   
│sda2      99%    699.9     14.0KB/s  178.0   4.0KB  493%    3658.8KB/s   1   
│dm-0       0%      0.0      0.0KB/s    0.0   0.0KB    0%       0.0KB/s   0   
│dm-1      99%    699.9     14.0KB/s  178.5   4.0KB  494%    3658.8KB/s   1   
│dm-2       0%      0.0      0.0KB/s    0.0   0.0KB   76%    2553.5KB/s   0   
│Totals Read-MB/s=2.1      Writes-MB/s=0.0      Transfers/sec=534.4 

In the above example I’m getting about 178 IOPS for my disk ’sda’

Method #2:
run fio with the correct workload (google how to use fio) and while it’s running it will actually tell you the IOPS.

[root@reddragon ~]# fio random-read-test.fio 
random-read: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1
fio-2.0.13
Starting 1 process
Jobs: 1 (f=1): [r] [85.1% done] [736K/0K/0K /s] [184 /0 /0  iops] [eta 00m:28s]

In this example I am getting 184 IOPS. Also if you wait until fio finishes it run - you can the IOPS reading from there. Eg.

random-read: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1
fio-2.0.13
Starting 1 process
Jobs: 1 (f=1): [r] [98.9% done] [2224K/0K/0K /s] [556 /0 /0  iops] [eta 00m:02s]
random-read: (groupid=0, jobs=1): err= 0: pid=7239: Tue Feb 25 16:49:16 2014
  read : io=131072KB, bw=747406 B/s, iops=182 , runt=179578msec
    clat (usec): min=107 , max=117530 , avg=5473.62, stdev=4112.08
     lat (usec): min=107 , max=117531 , avg=5473.93, stdev=4112.08
    clat percentiles (usec):
     |  1.00th=[  245],  5.00th=[  302], 10.00th=[  370], 20.00th=[ 2480],
<SNIP>

As you can see: iops=182 - pretty consistent with the other results!