Disk IO monopolized by one app

Question

Hi,
I have a desktop and a notebook, by hardware upgrade issues i'm using only my notebook,
On my desktop, i have four hard driver 7200RPM SATA II so i've only notices this problem when using VMWare and i  was thinking that was a VMWare problem, but, now that i'm using more the notebook i've noticed that this problem also affects my notebook, both are Arch Linux.
The notebook hard disk is slowest (it's one WD Blue that operates only at 5400RPM), so, this problem is more grave. When i open a process that consume much hard disk io, like a uncompress a file the Disk Input/Output is monopolized by that app and the system just "hangs" for some seconds, even minutes, until the operation is done.
On desktop i've only noticed that when the VM inside VMWare was using alot of bandwidth, but, on my notebook a simple system upgrade make my music stop until it's finish uncompressing the files, and the music only returns when that process stop to request so much IO. Just an example, both music, web navigation, anything. It's like the disk can't handle multiple access.
On my laptop i don't have VMWare or any heavy applications using the hard drive, only a simple system upgrade is enought to "freeze" the system for some seconds.
The system processor and RAM are ok, i've tested the disk IO usage with iotop, also, it's kinda perceptible that isn't a proc/mem issue.
Last edited by hoome (2013-08-22 17:04:42)

Answer 1

@Pse I was copying some movies (~200GB) from a Brand New 2TB 7200RPM 64MB Seagate SATA III Hard Drive to another Brand New 2TB 7200RPM 64MB Seagate SATA III Hard Drive on my desktop and the music stops and starts to buffer several times, not only the music, web browsing and general apps are slow (i think that they are trying to add data to the hard drive and getting the same problem as musics).
I managed to take a screenshot of iotop on one of those buffers:
Click to get bigger
@Pse i'm using ext4 with relatime and root reserved of 1%.
ps. those hard drivers are pratically empthy, has less than 10% of use.
Edit: And the genfstab add a option data=ordered on my fstab, what is it? has some relation with the problem? On my debian i jsut use relatime and rw options.
Last edited by hoome (2013-08-31 00:09:17)