High Disk Activity on Mac OS X

Question

I have noticed that disk activity is very high and I have been getting the spinning beach ball of death too. Does anyone have any ideas why or what I can do about it?

I am using Snow Leopard and used Activity Monitor to see the disk activity.

Answer 1

Could you be running out of RAM? You can check this in Activity Monitor, too. If you're short of RAM, memory could be being paged in and out (onto disk), slowing things down. The solution is to either install more RAM or run fewer programs at a time - are you running many when things go slow?

If it isn't RAM, it may be a particular program is doing lots of reading and writing - either intentionally (e.g. Photoshop used to use a scratch disk - I don't know if it still does) or unintentionally (e.g. trying to read and re-read a corrupt settings file). Is there a particular program that's always running when you have problems?

Answer 2

I wrote a script a while ago that lists the number of files every program has open. You can use it to see what program is doing all of the disk I/O.

#!/usr/bin/env python
import commands

lsof = commands.getoutput('lsof')
lsofs = lsof.split('\n')
proc = []
for x in lsofs:
    proc.append(x.split(' ')[0])

procc = {}
for x in proc:
    try:
        procc[x] = procc[x] + 1
    except KeyError:
        procc[x] = 1

procc = sorted(procc.items(), key = lambda(k,v):(v,k))

for x in iter(procc):
    print x[0] + ": " + str(x[1])