pci-e hardware raid controller

[Net Llama!]

On Wed, 6 Jun 2007, vu pham wrote:
> On Tue, 2007-06-05 at 14:50 -0500, Net Llama! wrote:
>> On Tue, 5 Jun 2007, Vu Pham wrote:
>>
>> SW RAID is generally as fast as the controller its sitting on.  You
>> shouldn't assume that HW RAID is faster than SW RAID.  Also, most people
>> looking to use RAID solutions aren't doing it for better performance.
>>
>
> I think raid 0 boosts the disk performance pretty well. I had two
> workstations each had a single scsi disk. After I add 3 more hdds onto
> each workstation and use raid-0, I can see all the apps are loaded much
> faster.

Sure, but RAID0 is just a big virtual disk.  So the performance is going 
to be about the same as the disks themselves.  Its RAID1 and up where 
things get alot more interesting in terms of performance.

>
> Raid 0 has more possibility of disk failure so I backup my two
> workstations everyday.

That's why RAID0 is little more than a toy from a reliability perspective. 
RAID5 tends to be the trade-off point between the features of RAID 1 and 
RAID0.  Of course there's also RAID 0+1 which has better performance than 
RAID5, assuming that you  have enough disks in the arrya.

>
> I am going to try the LVM. If the performance gain is good enough then I
> do not have to use the hardware raid and can  get more memory for my
> wks :)

I'm puzzled why anyone thinks that LVM is a substitute for RAID.  THey 
serve different purposes, and have little in common.


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lonni J Friedman                        netllama at linux-sxs.org
LlamaLand				http://netllama.linux-sxs.org