SATA vs SCSI

[Rob Nicholson]

I know, that old chestnut We're currently running a five year old Dell
PowerEdge 4400 server with 5 x 70GB Hitachi Ultra 160 SCSI drives in RAID-5
giving us ~280GB disk space. This server hosts our file share, SQL 7 and
Exchange 5.5 services.

But the time has come to plan for the future and upgrade where appropriate.
We're looking at switching to Windows 2003 and buying another server to host
SQL Server and Exchange. We're at about 40 users at the moment but have
plans to grow to 100+

Simple question, complex answer I guess: is it still best to stick with SCSI
or consider SATA? I've read some positive reviews of the SATA Raptor versus
SCSI systems. Cost isn't really the biggest issue - mainly want the best
technology for the next five years. Yeah, I know - impossible task

Thanks, Rob.

 

[Arno Wagner]

I know, that old chestnut We're currently running a five year old Dell
PowerEdge 4400 server with 5 x 70GB Hitachi Ultra 160 SCSI drives in RAID-5
giving us ~280GB disk space. This server hosts our file share, SQL 7 and
Exchange 5.5 services.

But the time has come to plan for the future and upgrade where appropriate.
We're looking at switching to Windows 2003 and buying another server to host
SQL Server and Exchange. We're at about 40 users at the moment but have
plans to grow to 100+

Simple question, complex answer I guess: is it still best to stick with SCSI
or consider SATA?

Stay SCSI. SATA may look the same in some benchmarks, but the
fact of it is that SATA is a cheap, mass-market product, while
SCSI is a professional product. It is designed with a different
mind-set. True, SCSI also fails sometimes. Also true SCSI may
not be that much faster today. But overall you get something
different when profit margins per unit are significanrt and
manufacturer care to have their products viewed as reliable
by people that are willing to pay a lot.

I've read some positive reviews of the SATA Raptor versus
SCSI systems.

Of course. WD does not have SCSI products and so has to make
everybody believe that SATA is just as good. It is not. And
frankly I would be concertned with the reliability (or better
lack of) WD disks.

Cost isn't really the biggest issue - mainly want the best
technology for the next five years. Yeah, I know - impossible
task

Best technology: SCSI, without doubt. These are expected to
run 24/7 for years.

Cheapest technology: SATA. And if you do not buy WD, but Samsung,
Seagate, or maybe new Hitachi, most of the disks may even be alive
in 5 years.

Arno

 

[Rob Nicholson]

Best technology: SCSI, without doubt. These are expected to

run 24/7 for years.

Also, one of the things that prompted me to look was that I was checking our
NAS and SANs and wandered into the Dell NAS offering which was SATA. That's
what got me thinking.

Cheers, Rob.

 

[Rob Nicholson]

Of course. WD does not have SCSI products and so has to make

everybody believe that SATA is just as good. It is not. And
frankly I would be concertned with the reliability (or better
lack of) WD disks.

True - we've had a couple of large WD fail with the click-of-death.

Best technology: SCSI, without doubt. These are expected to
run 24/7 for years.

I suspected as much but thought I'd ask.

Cheers, Rob.

 

[Rita Ä Berkowitz]

Simple question, complex answer I guess: is it still best to stick
with SCSI or consider SATA? I've read some positive reviews of the
SATA Raptor versus SCSI systems. Cost isn't really the biggest issue
- mainly want the best technology for the next five years. Yeah, I
know - impossible task

You have the best foundation for a great highly reliable system with a lot
of room for expansion. At this point in time there is no reason to go
backwards in technology and reliability by using SATA to save a few pennies.
I'm not sure what Hitachi drives you are using now, but if you have any
concerns about squeezing out a little more performance you should look at
replacing them with the latest generation Seagate Cheetah drives and
possibly the RAID controller. If you have the need to do any upgrades I
would suggest going U320 with the controller and Cheetah drives

As a general rule, SATA is reserved for systems used for gaming,
overclocking, MP3 servers for your teenagers, and other neon lighted cases
devoted solely for show. For maximum longevity of data retention and worry
free reliability there is no other solution than SCSI. For cheap drives
that are being used in novelty systems were reliability and data retention
is so far down the priority list the only choice would be SATA







Rita

 

[Rita Ä Berkowitz]

Also, one of the things that prompted me to look was that I was
checking our NAS and SANs and wandered into the Dell NAS offering
which was SATA. That's what got me thinking.

The Dell NAS (SATA) is great for immediate and temporary data exchange for
daily interoffice use and to supplement performance of your main server by
reducing workload during peak demand periods. Using it for long-term
storage is highly risky and isn't recommended for that purpose.







Rita

 

[chrisv]

As a general rule,

everyone should ignore"Rita" the SCSI troll.

 

[chrisv]

highly risky

....is listening to the advice of a known troll - "Rita".

 

[J. Clarke]

I know, that old chestnut We're currently running a five year old Dell
PowerEdge 4400 server with 5 x 70GB Hitachi Ultra 160 SCSI drives in
RAID-5 giving us ~280GB disk space. This server hosts our file share, SQL
7 and Exchange 5.5 services.

But the time has come to plan for the future and upgrade where
appropriate. We're looking at switching to Windows 2003 and buying another
server to host SQL Server and Exchange. We're at about 40 users at the
moment but have plans to grow to 100+

Simple question, complex answer I guess: is it still best to stick with
SCSI or consider SATA? I've read some positive reviews of the SATA Raptor
versus SCSI systems. Cost isn't really the biggest issue - mainly want the
best technology for the next five years. Yeah, I know - impossible task

You have to understand that for some people this is a religious issue. They
know with certainty on the basis of no information that one or the other is
"better".

In the real world it depends on your needs. If you need the highest
possible performance then SCSI is still the way to go--there is a wider
range of high performance SCSI hardware available, 15K RPM drives are
available from several vendors, there's a much wider range of hardware RAID
support available. You have to be careful in your system design
though--with SCSI it's possible for the SCSI bus to become the bottleneck.

If you need the highest _density_ then SATA has the edge--you can get 500 GB
SATA drives off the shelf now, today, from a number of sources while the
largest SCSI drive you can buy is only 300 GB. You can also get SATA
drives in 2-1/2" form factor from a number of vendors, while there's only
one manufacturer of 2-1/2" SCSI drives that I'm aware of. Manufacturers
tend to experiment a bit with SATA and IDE as well--the first perpendicular
recording drives for example just recently shipped and they are are IDE
laptop drives.

If you need the highest _availability_ on your system then things are not so
clear cut. Individually a SCSI drive will likely be somewhat more reliable
than an SATA drive. Collectively though, availability doesn't come from
the reliability of individual drives but from the reliability and
availability of the drive _system_. There, SATA has some advantages. The
big one is that it's not a shared interface--on a SCSI system if a drive
for example fails in such a way that it shorts one of the data lines to
ground it takes down the entire channel until it is removed. If you're not
running a mirror on another channel then your system goes down. SATA
doesn't have that problem--each drive is on a separate channel. There are
also several SATA RAID-6 solutions available--RAID 6 requires that _three_
drives fail before you lose data vs 2 for other RAID systems. This can be
implemented with SCSI drives in software under Linux but as far as I know
it's not available as a software solution under Windows as yet. So in
terms of system availability it's not clear that SCSI is the winner--what
will change is the frequency with which you have to replace failed drives
and I've seen no statistics on that that suggest that one or the other has
an edge.

 

[Arno Wagner]

Also, one of the things that prompted me to look was that I was
checking our NAS and SANs and wandered into the Dell NAS offering
which was SATA. That's what got me thinking.

Yes, me too. I now have an expensive ADAPTEC RAID controller lying
around. Unusable trash. No SMART monitoring, no commandline tools
(They have an interactive text-based shell that they claim is
a commandline tool. It is not.), unreliable with unusable
crash disgnostics. Definitely not a professional product.
Fits the mind-set I expect for (S)ATA.

Still you can use (S)ATA for you long-term reliable storage. You
just need to know what you buy and to add the reliability yourself.

Arno

 

[Arno Wagner]

Rita Ä Berkowitz wrote:

everyone should ignore"Rita" the SCSI troll.

Rita is tricky. She advises the right thing in some cases, but for the
wrong reasons. SCSI does not fit every need. On the other hand SCSI is a
perfect match for the sales people due to higher margins. That may be
why Rita advises it unconditionally.

If you need a lot of space, relatively high reliability and relatively
low speed and are willing to do some things yourself, a server farm
under Linux with software-RAID (for example) can be far superiour. It
can also be the only thing you can get if you need those 10TB but your
budget is limited.

Arno

 

[Peter]

I know, that old chestnut We're currently running a five year old Dell

PowerEdge 4400 server with 5 x 70GB Hitachi Ultra 160 SCSI drives in RAID-5
giving us ~280GB disk space. This server hosts our file share, SQL 7 and
Exchange 5.5 services.

But the time has come to plan for the future and upgrade where appropriate.
We're looking at switching to Windows 2003 and buying another server to host
SQL Server and Exchange. We're at about 40 users at the moment but have
plans to grow to 100+

Simple question, complex answer I guess: is it still best to stick with SCSI
or consider SATA? I've read some positive reviews of the SATA Raptor versus
SCSI systems. Cost isn't really the biggest issue - mainly want the best
technology for the next five years. Yeah, I know - impossible task

You may look at SAS technology. A few drives from Seagate:
http://www.seagate.com/cda/products/discsales/index/1,,,00.html?interface=SAS

As for the server, look at IBM x260:
http://www-03.ibm.com/servers/eserver/xseries/x260.html

 

[Folkert Rienstra]

Stay SCSI.

Ignore babblemouth.

SATA may look the same in some benchmarks, but the
fact of it is that SATA is a cheap, mass-market product,

Nonsense. SATA is used in Enterprise products as well.
Enterprise SATA is fine if you don't need the extra capabilities of SAS.

Dismissing SATA is dismissing SAS as well.

while SCSI is a professional product.

Nope. Enterprise SCSI is.

It is designed with a different mind-set.

Different needs.

True, SCSI also fails sometimes.

And more than you like.

Also true SCSI may not be that much faster today.

Depends on the application.
Fast is a relative term on a busy small record IO file server
or database server. There 'fast' means low access time.

But overall you get something different when profit margins per
unit are significanrt and manufacturer care to have their products
viewed as reliable by people that are willing to pay a lot.


Of course.

WD does not have SCSI products

Currently, but still have the knowledge from when they still made
them, only a few years back. Can't recall that they had a bad rep.

and so has to make everybody believe that SATA is just as good.

Ah, a conspiricy. Who would have thought.

It is not.

SATA (the standard) is fine and will mature more with every year of existence.

And frankly I would be concertned with the reliability (or better
lack of) WD disks.

Non Enterprise disks.
(And frankly I'm more 'concertned' with your 'significanrt' brain tumor).

Go SAS if you can wait a little. SCSI if you can't but know that there
won't be anymore progress in SCSI with U320 being the end technology.
SATA/Raptors if you want new technology that is somewhat proven by
availability for, what is it, 2 years now?

Best technology: SCSI, without doubt. These are expected to
run 24/7 for years.

Only the Enterprise ones.

Cheapest technology: SATA. And if you do not buy WD, but Samsung,
Seagate, or maybe new Hitachi, most of the disks may even be alive
in 5 years.

Raptor should be fine. It's the only 10krpm (non-SCSI) Enterprise drive.
The latest version is even more 'SCSI' like with it smaller sized platters.

 

[Andy]

I know, that old chestnut We're currently running a five year old Dell
PowerEdge 4400 server with 5 x 70GB Hitachi Ultra 160 SCSI drives in RAID-5
giving us ~280GB disk space. This server hosts our file share, SQL 7 and
Exchange 5.5 services.

But the time has come to plan for the future and upgrade where appropriate.
We're looking at switching to Windows 2003 and buying another server to host
SQL Server and Exchange. We're at about 40 users at the moment but have
plans to grow to 100+

Simple question, complex answer I guess: is it still best to stick with SCSI
or consider SATA? I've read some positive reviews of the SATA Raptor versus
SCSI systems. Cost isn't really the biggest issue - mainly want the best
technology for the next five years. Yeah, I know - impossible task

seems like SCSI will be best for your requirement because
it's a lot more reliable & higher performing that SATA, especially
in IOP (database, OLTP, etc. applications while SATA is a great
way to save $$ if your requirement is either a streaming one
(digital video editing, tape backup emulation, etc.)

& don't forget, SCSI is turning to SAS (serial attached scsi)
right now and that means that you can buy storage subsystems
that have drive slots that take a mix of SATA & NSAS drives
(think of a RAID with 5 SATA drives in one array for your DVE
application & 10 SAS drives for your OLTP & database requirements

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[dannysdailys]

Rob Nicholson wrote

As a general rule, SATA is reserved for systems used for gaming
overclocking, MP3 servers for your teenagers, and other neon lighte case
devoted solely for show. For maximum longevity of data retentio and worr
free reliability there is no other solution than SCSI. For chea drive
that are being used in novelty systems were reliability and dat retentio
is so far down the priority list the only choice would be SATA Rit

You know, I was content to let you all get away with SCSI until this

Sorry Rita darling, SATA is a proven platform. I use it in variou
machines and have no trouble with it at all

I have data thats been around for over 20 years and they are all o
SATA at this time. I feel quite safe with it. I'm not even sure yo
need Raptor drives

Western Digital makes some of the most reliable hard drives in th
industry. That's a fact, Rita..

The only trouble I ever had was with SCSI. It killed an entir
system. Yes, that was quite some time ago. But I only give on
chance to systems. Especially when they're still quite new

SATA system are cheap, and reliable. I just retired a set of Maxto
Diamond Max drives that were two years old. They're so cheap, yo
just replace them in the RAID array if you even have a hint o
doubt

SATA 2 on a server array can't be beat for speed

SCSI is old, it's slow, and it's expensive. You guys sound lik
Intel; the last gasp

 

[Eric Gisin]

You know, I was content to let you all get away with SCSI until this.

Sorry Rita darling, SATA is a proven platform. I use it in various
machines and have no trouble with it at all.

I have data thats been around for over 20 years and they are all on
SATA at this time. I feel quite safe with it. I'm not even sure you
need Raptor drives.

Western Digital makes some of the most reliable hard drives in the
industry. That's a fact, Rita...

The only trouble I ever had was with SCSI. It killed an entire
system. Yes, that was quite some time ago. But I only give one
chance to systems. Especially when they're still quite new.

SATA system are cheap, and reliable. I just retired a set of Maxtor
Diamond Max drives that were two years old. They're so cheap, you
just replace them in the RAID array if you even have a hint of
doubt.

SATA 2 on a server array can't be beat for speed.

SCSI is old, it's slow, and it's expensive. You guys sound like
Intel; the last gasp.

What a moron. You obviously have no server experience.

Look at storagereview.com's Raptor 150GB review - multiuser.
10K SCSI beats the Raptor, 7200 SATA doesn't even come close.

 

[Rita Ä Berkowitz]

You know, I was content to let you all get away with SCSI until this.

I take it you are a gamer and also use AMD processor(s)

Sorry Rita darling, SATA is a proven platform. I use it in various
machines and have no trouble with it at all.

Absolutely! I never said it wasn't a "proven platform" since I gave you
real world applications were SATA shines. Unfortunately it's not in any
mission critical application where reliability can mean the difference
between life and death. SATA excels in the AMD crowd were the users are
only worried about measuring their manhood by how many GBs they have under
the hood.

I have data thats been around for over 20 years and they are all on
SATA at this time. I feel quite safe with it. I'm not even sure you
need Raptor drives.

Tell me that in another 20-years. Better yet, how about 5-years?

Western Digital makes some of the most reliable hard drives in the
industry. That's a fact, Rita...

Seagate Cheetah! Is there really anything else?

The only trouble I ever had was with SCSI. It killed an entire
system. Yes, that was quite some time ago. But I only give one
chance to systems. Especially when they're still quite new.

Which is most likely attributed to pilot error. You crashed and burned
because of something you failed to do, like RTFM.

SATA system are cheap, and reliable. I just retired a set of Maxtor
Diamond Max drives that were two years old. They're so cheap, you
just replace them in the RAID array if you even have a hint of
doubt.

SCSI is far cheaper! Plus I *NEVER* doubt the SCSI arrays and solutions I
have deployed for my customers. Sure SATA drives are initially cheaper than
SCSI, but you get what you pay for. When downtime, lost productivity,
labor, and support costs are figured into the equation SATA solutions are
generally three to four times more expensive than SCSI over the predicted
life of the equipment.

SATA 2 on a server array can't be beat for speed.

It's been beaten before it was ever conceived. Hell, even an antiquated
narrow SCSI drive kills SATA.

SCSI is old, it's slow, and it's expensive. You guys sound like
Intel; the last gasp.

List an example of a SATA drive that can beat the seek time and overall
performance of the latest generation 15K U320 Seagate Cheetahs? After you
do that we'll then discuss and compare reliability.

Like I said if I wanted to build a novelty box I would definitely go SATA.
If I wanted to have a space heater to keep my feet warm on a cold winters
night I would use AMD processors.







Rita

 

[Rob Nicholson]

Still you can use (S)ATA for you long-term reliable storage. You

just need to know what you buy and to add the reliability yourself.

We have a development server with 300GB x 2 and 400GB x 2 SATA RAID onto
which we store PC images, CD-ROM images and an archive of old data off the
main data server. Works a treat, cost peanuts and it's backed up onto (a
lot) of LTO tapes one a month. The data on there is old anyway so once a
month is fine.

Rob.

 

[Rob Nicholson]

You have to understand that for some people this is a religious issue.

They
know with certainty on the basis of no information that one or the other
is
"better".

As I'm findiing

support available. You have to be careful in your system design
though--with SCSI it's possible for the SCSI bus to become the bottleneck.

We currently have a Dell PowerEdge 4400 with 5 x 76GB hard disks in a RAID-5
configuration and it's been (touch wood) incredibly reliable over the past
five years. This is running Back Office, i.e. NT 4. But time moves on hence
the reason for looking around.

If you need the highest _density_ then SATA has the edge--you can get 500
GB

Don't need that much - we've got ~256GB with the existing system but I'm
currently trying to look into the future. I guess we'd put reliability,
speed and capacity in that order.

Cheers, Rob.

 

[Rob Nicholson]

seems like SCSI will be best for your requirement because

it's a lot more reliable & higher performing that SATA, especially
in IOP (database, OLTP, etc. applications while SATA is a great

Our use is primarily office type stuff with some database access but not
heavy.

& don't forget, SCSI is turning to SAS (serial attached scsi)
right now and that means that you can buy storage subsystems
that have drive slots that take a mix of SATA & NSAS drives
(think of a RAID with 5 SATA drives in one array for your DVE
application & 10 SAS drives for your OLTP & database requirements

I'm tempted to stick with SCSI for now (getting a new Dell server with it
all inside) with five drives in RAID-5. We'll continue to experiment and try
out SATA in less critical systems.

Cheers, Rob.