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

Re: [SOLVED] Re: Partitioning And Formatting A Large Disk (2086.09GB)

On Thu, Feb 01, 2007 at 01:06:54PM -0500, Michael S. Peek wrote:
> So the consensus seems to be that LVM is the way to go.
> So what's the cutoff between building arrays of varying size versus 
> grouping them under LVM?
> I.e. Right now I've got two large arrays.  Should I maybe break that 
> down unto just a bunch of disks and then use LVM to group them together 
> (not use hardware RAID at all), or should I break the disks into each 
> bundles of three and make as many small raid5 arrays as I can and then 
> group them under LVM?

well the thing with LVM is if you have a disk failure one layer below
the lvm then you've likely lost a bunch of data. Only if you're lucky
enough to not have any extents on the failing disk will you not lose
data. Fat chance that. By using RAID you are moving that disk failure
down another layer from the lvm. A single disk failure when you have
jbod under lvm means your toast. A single disk failure when you have
RAID under lvm means you have and intact lvm running on a degraded
array -- a much preferable situation ;-)

I think the great utility of lvm is not in the combining of multiple
volumes into a big volume group but instead in the flexibility of
being able to shuffle around your file systems as needed. So I
wouldn't give up the reliability bonus of RAID underneath lvm. That
way if you have a disk in your array fail, you still have a valid lvm
setup over the top of it. 



Attachment: signature.asc
Description: Digital signature

Reply to: