On Sat, Mar 24, 2012 at 05:41:40PM +1100, Anthony Shipman wrote:
Wikipedia says that VT-d is Intel's idea of an IOMMU.
you're right i just read the first few lines of the wikipedia page and thought "it's intel's virtualisation cpu flag....not what i'm looking for"
But my BIOS doesn't show it despite what the manual says. There is nothing else in the BIOS resembling an IOMMU
on futher reading...it IS the iommu setting on intel. try turning it off. (i'm far more used to amd systems and bios settings than intel ones)
or memory hole remapping.
memory hole remapping is where the huge chunk of memory used by a modern GPU (up to 3GB on some cards) is mapped out of lower memory. there's probably a setting for it somewhere....some BIOSes have settings in extremely weird places (a HP desktop machine i needed to run kvm on a few weeks ago had virtualisation support under "Security" in the BIOS. would never have thought of looking for it there, only found it by exhaustive search of every single option)
The controller was in IDE mode. I've changed it to AHCI.
good. that's the native mode for sata these days, ide mode is an emulation for older operating systems (i.e. win xp. or even a later version of windows that was installed on IDE but has been upgraded to sata drives & controller. linux is cool with the underlying hardware changing - at worst, the device name may change so fstab might need editing - but windows doesn't like it at all, and it can be a real pain getting windows booting again if you change the drive type). in short: ahci gives you the full feature set of ahci and (probably) better performance.
what happens if you do something like 'dd if=/dev/sdb5 of=/dev/null'
No fault at all (with the controller in IDE mode).
I'll have to wait and see what happens next.
did you try the write test as well? one other thing to try - should have suggested it earlier. unmount the XFS file system (boot to single-user if necessary) and run xfs_check and/or xfs_repair on it. if the fs has been corrupted badly enough in the past (e.g. due to a crash or power failure), xfs can get terribly confused when it encounters the corruption again. worst case if it's corrupted so bad that xfs_repair can't fix it, you'll have to backup and restore. craig -- craig sanders <cas@taz.net.au> BOFH excuse #393: Interference from the Van Allen Belt.