[NTLUG:Discuss] NAS devices

[Chris Cox]

Ralph wrote:
> Howdy,
>   I get to spec out and probably buy a NAS for the office.  I see some 2
> U servers that have 8 exposed 2.5 inch drive bays.  When I think of 2.5
> inch hard drives, I don't think of drives that can take heavy use.  Are
> these new drives built better than laptop drives?  Is SAS better than
> SATA?  SAS drives seem to go up to 146 GIG and SATA up to 500 GIG.  At
> least, that is what Pogo Linux says.  I don't need huge amounts of
> throughput.  But, reliability is very important.  Any comments?

My opinion....

A RAID'd set of drives hides a multitude of sins.

So while SAS is better than SATA in a SINGLE drive case.
Across many RAID'd drives, you simply will NOT see the
performance differences.  Also, if we're talking NAS,
that will also hide any performance differences.  So...
IMHO, go SATA with RAID.  The cost of replacing the SATA
drives will still be less than the SAS cost over the
long haul.  Especially if you consider how much larger
SATA drives are.

In the past, I used Arena RAID units (those use PATA
drives).  In fact, we'll be retiring a 16 bay unit
sometime this year.  It has had ONE drive failure over
7 years (16 x 160GB WD drives).  Performance (native)
is around 75-90MB/sec.  Of course, you'll be bound
by your network speed.  Un-tuned NFS across a gigabit
link will get you over 35MB/sec.

BEWARE of the cheapy NAS boxes at Fry's etc.  There
are some that CLAIM to be gigabit, but if you read
the fine print, they max out at like 190Mbit or something
stupid like that... which isn't terribly more than
what you'd get with a 100Mbit unit.  You'll probably
get better performance from a USB attached drive than
you will get with a lot of those units.

I'd look at a JanusRAID (entry level SA-4340S) today and
direct attach it SCSI wise to a Linux host to provide the NAS.
I'd go gigabit if you can.  We use HP DL380 servers.

Our current NAS connects to storage off of a SAN, which
may be a bit pricey... though certainly an option.
You can go to http://maxtronic.com to see some other
models.  If you want a "deal" on something new, contact
Jeanne Wilson at http://condorstorage.com/contact_info.htm

Oh... and yes... I've been operating our NAS infrastructure
for almost 8 years now.. and apart from doing upgrades
(done about 3 during that time period), we've had ZERO
downtime (well.. we did have a firmware issue... on one
of our SAN units... but it wasn't caused by Linux/NAS).

Oh.. and SATA goes over 1TB now.. just fyi.  We have
a 42 drive unit with 1TB drives in it.