Re: [Qemu-devel] Re: Notes on block I/O data integrity

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Christoph Hellwig wrote:
> > what about LVM? iv'e read somewhere that it used to just eat barriers
> > used by XFS, making it less safe than simple partitions.
> 
> Oh, any additional layers open another by cans of worms.  On Linux until
> very recently using LVM or software raid means only disabled
> write caches are safe.

I believe that's still true except if there's more than one backing
drive, so software RAID still isn't safe.  Did that change?

But even with barriers, software RAID may have a consistency problem
if one stripe is updated and the system fails before the matching
parity stripe is updated.

I've been told that some hardware RAID implementations implement a
kind of journalling to deal with this, but Linux software RAID does not.

-- Jamie
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux