On 2012-11-07 16:02, Edward Ned Harvey (opensolarisisdeadlongliveopensolaris) wrote:
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
boun...@opensolaris.org] On Behalf Of Tiernan OToole

I have a Dedicated server in a data center in Germany, and it has 2 3TB drives,
but only software RAID. I have got them to install VMWare ESXi and so far
everything is going ok... I have the 2 drives as standard data stores...

ESXi doesn't do software raid, so ... what are you talking about?

I believe he could mean the RAID done by motherboard/chipset and
utilizing the CPU for its work. Not all OSes even recognize such
"mirrors", i.e. on one of my old systems with a motherboard-made
HDD mirror, the Linux livecd's always saw the two separate disks.

There was recently a statement on the list that all RAIDs are in
software. While pedantically true, the "hardware RAIDs" usually
have separate processors ("XOR engines" and so on) to deal with
redundancy, own RAM cache (perhaps with own battery-backed power
source), and the HDD bandwidths and IO paths are often untied
from storage representation to the rest of the host. So there
is some dedicated hardware thrown at "hardware RAID", as opposed
to that done by an OS or by additional BIOS/chipset features.

As I wished some years back, ZFS executed on a "RAID HBA" card
with its own CPU and RAM, and serving ZVOLs as SCSI LUNs to its
hosting computer running any OS would make for a wonderful product.
Then again, this is already done (possibly cheaper, better and
more highly available) by external NAS with a ZFS-aware OS inside...


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