[nmglug] RAID, SCSI vs ATA

[Jim Coberly]

Tim and all,

Just a couple of general information comments based on experience, probably
already in your thoughts.

1.  RAID tends to work well, but think about this.  If one builds a RAID
array with all hardware of similar vintage and kind, then there is a
likelihood of one or more disk drives failing at nearly the same time.  In
other words, they are all setup, configured and begin use at the same time
so if one disk fails, what is the assurance of the others continuing in
service?  So, it is my recommendation you consider backup of the data to
whatever media you can reasonably afford.

2.  SAN or NAS also fail.

So, a regular backup (and validated restore) process is critical to keeping
valuable data/information.

Jim C

On Jan 21, 2008 9:44 AM, Andres Paglayan <andres at paglayan.com> wrote:

>
> On Jan 21, 2008, at 9:24 AM, Aaron wrote:
>
> > 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
>
> western digital at sams has a 1tb box for $300
> although this should be ok only for home,
> or for "remote" (as in I take the HD home) backup,
>
> >
> > I have been looking at similar systems for work.
> > To save $$, I think it is cheapest to just build
> > a box.  Mid or full tower,  mobo with many, many SATA ports.
> >
> > The biggest storage/$ these days seems to be 500GB SATA drives.
> > It is getting rare to have large numbers of IDE (PATA) ports these
> > days.
> >
> > I have had trouble finding cheap cards with many SATA ports.
> > If anybody knows where to find them, let me know.
>
> nope, as you said, it's cheaper to get a mobo with an insane quantity
> of sata ports
>
> >
> > When I do see multiple SATA cards, they have RAID in them and
> > are more $$ 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.
>
> there are some with up to 12,
> http://www.newegg.com/Product/Product.aspx?Item=N82E16813131146R
>
> asus @ $214
>
>
> >
> > 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.
>
> not suer, but may be you can turn smart on and run some cron to query
> that will be emailed to you
> may be there's already some tool for that,
>
> >
> > 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
> >
> >
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