Hey, Activity Monitor tells me that my hard drive is working hard every time my computer gets painfully slow but it won't tell me what is accessing the hard drive or at what rate an app is doing so.

Anyone know what will do this?

you should be able to tell by sorting the processors by cpu usage and guessing. not too hard.

You are serious aren't you?!

An app could use 5% CPU and 95% HDD while another could use 95% CPU and 0% HDD

generally they are both in the same if it is a problem

just try it anyway, what do you have to lose

Obviously I've looked before I got here

I have at least 25 processes running with none more than 5% CPU.

So, does anyone know a program that will tell me which applications are using the hard drive and how heavily they are using it?

Timothy writes...

So, does anyone know a program that will tell me which applications are using the hard drive and how heavily they are using it?

It's called troubleshooting. Without investigation, I'd more than likely say it's got something to do either with Rosetta based and/or memory hungry applications. When your machine slows down as the disks thrash, what state is your machine's memory in? If you have next to no free memory, then increasing your memory will free your drive to service the requests from active applications.

I agree with the above - if my HDD starts going nuts, it's generally because some application working with it and I can see it with CPU spikes. Perfect example is mds (Spotlight indexing).

Check for process with lots of threads (possible that threads are leaking memory), but like mentioned above, the HDD is going nuts randomly if memory is low and lots of paging is going on.

'top' doesn't include such information, in fact I've never seen monitors that monitor HDD usage on a process-by-process basis. A waste of clock cycles if you ask me.

So, does anyone know a program that will tell me which applications are using the hard drive and how heavily they are using it?

Timothy writes...

So, does anyone know a program that will tell me which applications are using the hard drive and how heavily they are using it

this will tell you every file that every process has open
lsof

dfunked writes...

but like mentioned above, the HDD is going nuts randomly if memory is low and lots of paging is going on.

Yeah, What are your page ins/outs Numbers ???

A quick question, how much memory do you have in your machine?

If you only have a limited amount of ram, then it is more than likely that you will have applications paging off to disk.

This will do two things, firstly it will slow down things a lot due to the paging, secondly it will slow things down due to the additional load on the system to handle the paging.

Fire up activity monitor and have a look at the System memory tab. This will show you how much of the memory is being used. If you have 0 free then you will be in trouble.

You can also see what paging in and out is happening there.

How about quitting your applications one by one and seeing if there's a change in activity? If you have quit them all and the drive is still being thrashed then it's a system problem/process.

Johno writes...

Fire up activity monitor and have a look at the System memory tab. This will show you how much of the memory is being used.

that wont tell you as much as page ins/out will .

OK Found IT

sudo fs_usage -f filesys

use control + c to kill it (if you didn't know that already)

Agreed that the Unix command will tell you a lot more than activity monitor. However if you are a novice understanding what you are seeing may be a bit difficult.

The Activity Monitor at least provides a nice graphical summary of memory use, and identifies the number of page outs that have occurred. It will also show what processes are using what memory and CPU.

This is why I usually point people in that direction first.

Johno writes...

if you are a novice understanding what you are seeing may be a bit difficult.

How would anyone learn then ?

bigkm writes...

How would anyone learn then ?

Agreed. However there are people that wish to use a computer as an appliance. They do not desire, or potentially have the time, aptitude or capability to learn the underlying nuances of the Unix operating system.

Apple is marketed as an easy to use alternative to windows. IMO going down to command line activities in unix, especially where they need to be run at super user level, is not what I would call user friendly.

Yes there are many people who love to learn and understand the complexities of computers. There are many more who just want to use them, without all the maintenance overhead that they require.

The Mac usually caters better for these people than Windows. I guess neither of us asked the OP what level of skills he had, and what he had done so far, and whether he was just looking for a solution, or obtaining the knowledge as to how better use his system at a lower level.

In that respect we both jumped to conclusions as to how we could best help him.

bigkm writes...

OK Found IT

Thank you SO much bigkm, that is EXACTLY what I need

It will take some time to analyse the data but I now actually have a way to do true, byte by byte, analysis.