VMware crashes after updating (upgrading) of host OS (to CentOS 5.4)

If you have in your hostd.log something like this:

Nov 07 21:19:12.648: Worker#23| Caught signal 6 -- tid 31543

this can be related with update(upgrade) of host OS.

After upgrading of a host OS (CentOS 5.3->CentOS 5.4) I got an issue - a guest OS started to crash. Searching around for a possible cause I found bug post in CentOS bug tracker. Seems that issue is related to glibc update (last version is glibc-2.5-42) and a fix is to downgrade to previous version on host OS (glibc-2.5-34).

To be sure that your downgrade of glibc worked - check the size of libc-2.5.so. I got an issue on downgrade (even with --oldpackage rpm was not willing to replace a libc), and that's why I lost some hours trying to figure out what is going on. So, be sure to check the size of the files after downgrade. It can save you some hours :)

Twitter tip

RT @ryancarson: Top tip: You can put a "+" on the end of any http://bit.ly link and see, real time, the pace at which that link is getting shared and clicked

VMware troubles

Well, I'm not a hardware guru, but from my experience I figured out the following:

Dell Servers + QLogic HBA + IBM Storage = troubles

Dell Servers + Emulex HBA + IBM Storage = working ok

Dell Servers + QLogic HBA + EMC Storage = working ok

Other one issue is:

Any server + Any HBA + Any storage - Fiber Channel Switch = troubles (unclean filesystem on Linux guests with EXT3 filesystem)

"Network Connection Closed Unexpectedly" error while using svn+ssh

If you got a "Network Connection Closed Unexpectedly" error while using svn+ssh (here is a nice HOWTO) then you should comment (or remove) "mesg y" in /etc/bashrc or in $HOME/.bashrc

Worked for me as a charm :)

iPhone speaker too low

Well, I got a simple accident - "Mozart Chocolate Liqueur" were split over my iPhone 3G. I quickly clean it out, but... Next day I noticed that my iPhone speaker was too low. I was not able to hear it ringing. After looking around for solution I found a post telling that this can be caused by dust. Seems that this is my case (ok, not dust, but a creamy liqueur...). 

So, I put some music on my iPhone and start carefully cleaning the microphone hole with a needle. After just a few holes I made on the "dust" - I was able to hear that volume had increased. So I finished up cleaning by putting a needle just a little into every tiny hole of the speaker protection and everything worked like a charm. My speaker volume came back to the normal level (or even louder).

Just in case that you have a doubt on which one is speaker and which one is microphone on your iPhone - here is a picture:

How to sync Google Contacts and Calendar with iPhone

I've been looking for some simple solution to sync Google Contacts & Calendar with my iPhone on the air (without syncing with my notebook). Finally I found a solution that seems to be working like a charm.

https://www.nuevasync.com/

Setup process is quite simple and straigh forward. 

cfmenu and cfgrid overlap

If you are using <cfmenu> and <cfgrid> and you have an overlapping of the menu items by cfgrid header (a part of menu is hidden behind cfgrid header) you must add to your CSS a following style:

#myMenuId .yuimenu {

z-index: 300003;

}

This problem is caused by some "yui" CSS style with z-index set to 1, while grid related styles have z-index bigger than 200000.

ESX host not connecting to Virtual Center

We got following problem some days ago:

One of our ESX (version 3.5) hosts, after crash, was not connecting to Virtual Center (version 2.5).

Solution:

• Restart management service on ESX host

service mgmt-vmware stop

service mgmt-vmware start

• Restart Virtual Center service on Virtual Center server (stop/start on service VMware Virtual Center in Services)

One more stuff - if you have a lot of memory on your hosts (16 GB or more) I would recommend you to increment amount of console memory on your host to 800 MB. You can do this in "Configuration" tab for host in your Virtual Center console.

Creating a copy of the disk (vmdk) in VMware

When you need to have the a copy of the disk from one VM on the other:

• Power off  source VM, copy your .vmdk files to destination VM (probably you would like to change disk name and flat name - just rename your files and edit smaller .vmdk file to set correct name for flat file).
  
• Set new UUID for your copy of your original .vmdk file

/usr/sbin/vmkfstools -J setuuid path_to_destination_VM/filename.vmdk

• Add new disk to your destination VM (using "Use an existing virtual disk" option)
• Start your VMs (source and destination)
• Mount new drive on your destination machine

We used this solution to make a quick copy of data files disks from primary Oracle server to standby Oracle server.

Oracle analog of MySQL GROUP_CONCAT function

I was looking for Oracle analog of MySQL GROUP_CONCAT function. There is a solution on Ask Tom site. So here it is:

create or replace type string_agg_type as object (

  total varchar2(4000),

  static function ODCIAggregateInitialize(sctx IN OUT string_agg_type )

  return number,

  member function ODCIAggregateIterate(self IN OUT string_agg_type, value IN varchar2 )

  return number,

  member function ODCIAggregateTerminate(self IN string_agg_type, returnValue OUT varchar2, flags IN number)

  return number,

  member function ODCIAggregateMerge(self IN OUT string_agg_type, ctx2 IN string_agg_type)

  return number

);

/

create or replace type body string_agg_type is

  static function ODCIAggregateInitialize(sctx IN OUT string_agg_type)

  return number

  is

  begin

    sctx := string_agg_type( null );

    return ODCIConst.Success;

  end;

  member function ODCIAggregateIterate(self IN OUT string_agg_type, value IN varchar2 )

  return number

  is

  begin

    self.total := self.total || ',' || value;

    return ODCIConst.Success;

  end;

  member function ODCIAggregateTerminate(self IN string_agg_type, returnValue OUT varchar2, flags IN number)

  return number

  is

  begin

    returnValue := ltrim(self.total,',');

    return ODCIConst.Success;

  end;

  member function ODCIAggregateMerge(self IN OUT string_agg_type, ctx2 IN string_agg_type)

  return number

  is

  begin

    self.total := self.total || ctx2.total;

    return ODCIConst.Success;

  end;

end;

/

create or replace function stragg(input varchar2)

return varchar2

parallel_enable aggregate using string_agg_type;

/

After this you can use this function like this:

select t1.id, stragg(t2.name) as names from table1 t1, table2 t2 where t1.id=t2.id group by t1.id;

It will produce comma separated list of the names - something like this:

ID NAMES

-- ------------------------------------

10 CLARK,KING,MILLER

20 SMITH,FORD,ADAMS,SCOTT,JONES

30 ALLEN,BLAKE,MARTIN,TURNER,JAMES,WARD