[nmglug] RAID, SCSI vs ATA

[Aaron]

Andres Paglayan wrote:
> I am kind of tackling the same things at home,
> new hi-res camera, and lots of stuff to store,
> and so far I am considering getting whatever mobo supporting several  
> (5 to 8) sata disks,
> and starting with 3 or 6 500GB raided drives,
> roughly $450 for 1TB or $750 for 2,5 TB

I have been looking at similar systems for work.
To save $$, I think it is cheapest to just build
a box.  Mid or full tower,  mobo with many, many SATA ports.

The biggest storage/$ these days seems to be 500GB SATA drives.
It is getting rare to have large numbers of IDE (PATA) ports these days.

I have had trouble finding cheap cards with many SATA ports.
If anybody knows where to find them, let me know.

When I do see multiple SATA cards, they have RAID in them and
are more $$ than I was planning on spending for the most of the system!

I have seen some higher-end Mobo's for around $200 that have 6-8 SATA ports.

Then run LINUX SW RAID.  I'm leary of learning *bsd software raid, since
even the LINUX SW RAID took some time to learn.  My boss will not
be happy about me billing for that learning curve again.

My take on SW raid is that you need to be a little careful.
SW RAID5 is a bit risky, IMOHO.
RAID5 will detect and recover from a disk FAILURE, but will be totally
unaware of a DISK CORRUPTION event.   RAID6 can catch these.
So, if you care about reliability, I'd stick to RAID-1 or RAID-6.

With disks so relatively cheap these days, RAID1 can make a lot of 
sense.  At least recovery is easy.   RAID6 seems cumbersome,
unless you are using more than 6 platters or so on your array.

I haven't done RAID1 yet, but for larger arrays, I'd want
to LVM (or RAID0) together two large block devices,
then build your RAID1 (Unless RAID1 will allow several devices...
not just two.  I dunno)

For RAID6, I would just build one giant RAID device, then split it
up if necessary with something like LVM.

            aaron