[Linux-cluster] iSCSI GFS

[gordan at bobich.net]

On Mon, 28 Jan 2008, isplist at logicore.net wrote:

>>> So basically, can't lose more than one storage chassis.
>>>
>> You can't lose more than 2.
>
> This is if I go with the RAID right? Do you have any thoughts on creating a
> large volume vs using virtual RAID to tie all of the storage devices together?

I must admit I'm not a huge fan of volumes. Ever since software RAID 
gained the ability to dynamicall add disks to a RAID stripe, I've not seen 
much point in it. The only useful features LVM will give you are snapshots 
(of questionable use as your FS won't necessarily be consistent, so it's 
not usable as a backup tool) and the ability to span multiple RAIDs.

At some point, statistically, RAID6 will cease providing enough 
redundancy. At that point, you need to switch to some higher level of RAID 
(e.g. m+n type RAID, of which I am not aware of an available software 
implementation of), or use LVM to span multiple arrays (i.e. JBOD of RAID6 
arrays).

Gordan