DDevelopment & Design

mount.ntfs high cpu ubuntu

My computer suffers from sudden and continous hard drive load strokes. Sometimes it lasts for a few minutes and hence work is impossible because everything goes very slow.I’m trying to locate the cause because it makes me nervous :)Today I found one of…

My computer suffers from sudden and continous hard drive load strokes. Sometimes it lasts for a few minutes and hence work is impossible because everything goes very slow.
I’m trying to locate the cause because it makes me nervous :)

Today I found one of the causes. It’s updatedb.mlocate script which is responsible for scanning hard drives and build locate (a location of files) database. But due to some NTFS driver limitations that poor thing thinks that NTFS share is always new and needs to be rescan at every scheduled scan.

How to make sure that you have the same problem? When hard drive starts to choke check all IO processes with

sudo iotop

and look for updatedb.mlocate or mount.ntfs processes with high IO load. If this is the case try to fix it.
The solution is to point NTFS shares as non-scannable. To do this edit

/etc/updatedb.conf

and add your NTFS mount paths to PRUNEPATHS list. Although NTFS is listed in PRUNEFS entry that dummy mlocate script still would scan NTFS shares.

All that I found on Ubuntu forum.

— Previous article

<!--:pl-->TouK jest w trasie<!--:--><!--:en-->TouK is on tour<!--:-->

Next article —

Managing gang of chaotic developers is complex

You May Also Like
DDevelopment & Design

micro-burn has Trello integration

After a few long evenings I've finally integrated micro-burn with Trello. All you need to run it for your Trello board is to write short configuration and run fat jar. It renders burndown chart visualising progress of cards on your board.You can specif...After a few long evenings I've finally integrated micro-burn with Trello. All you need to run it for your Trello board is to write short configuration and run fat jar. It renders burndown chart visualising progress of cards on your board.
DDevelopment & Design

Private fields and methods are not private in groovy

I used to code in Java before I met groovy. Like most of you, groovy attracted me with many enhancements. This was to my surprise to discover that method visibility in groovy is handled different than Java!

Consider this example:

class Person {
private String name
public  String surname

private Person() {}

private String signature() { "${name?.substring(0, 1)}. $surname" }

public String toString() { "I am $name $surname" }
}

How is this class interpreted with Java?

  1. Person has private constructor that cannot be accessed
  2. Field "name" is private and cannot be accessed
  3. Method signature() is private and cannot be accessed

Let's see how groovy interpretes Person:

public static void main(String[] args) {
def person = new Person()   // constructor is private - compilation error in Java
println(person.toString())

    person.@name = 'Mike'       // access name field directly - compilation error in Java
println(person.toString())

    person.name = 'John'        // there is a setter generated by groovy
println(person.toString())

    person.@surname = 'Foo'     // access surname field directly
println(person.toString())

    person.surname = 'Bar'      // access auto-generated setter
println(person.toString())

println(person.signature()) // call private method - compilation error in Java
}

I was really astonished by its output:

I am null null
I am Mike null
I am John null
I am John Foo
I am John Bar
J. Bar

As you can see, groovy does not follow visibility directives at all! It treats them as non-existing. Code compiles and executes fine. It's contrary to Java. In Java this code has several errors, pointed out in comments.

I've searched a bit on this topic and it seems that this behaviour is known since version 1.1 and there is a bug report on that: http://jira.codehaus.org/browse/GROOVY-1875. It is not resolved even with groovy 2 release. As Tim Yates mentioned in this Stackoverflow question: "It's not clear if it is a bug or by design". Groovy treats visibility keywords as a hint for a programmer.

I need to keep that lesson in mind next time I want to make some field or method private!