Comment 6 for bug 343371

I had a problem with a sata disk under heavy I/O ... response time degraded when loading/starting new applications (... until the disk finally freezed).

I solved my problem by fine tunning the "pdflush" parameters...

Monitor the "Dirty" values in " cat /proc/meminfo" ... if the values remain high (... are not cleaned frequently enough) then the problem might be the "pdflush" configuration.

If the problem is the "pdflush" then check this link :
https://bugs.launchpad.net/ubuntu/+bug/270794/comments/12

... I hope it helps.