Windows Server - New Servers - Sata vs SCSI and RAID Options

Asked By TheScullster

27-Jan-10 11:33 AM

Hi all

I am looking to replace our ageing File/Print and Exchange servers and would
welcome opinion on the above subjects:

For the drive arrays, there seems to be a trend towards SATA drives for
array builds.
I have approx 20 PC users running SATA drives, with no failures in the last
five years.
However I have had 2 failures in 6 months in a cluster of 4 servers running
SCSI arrays.
This would tend to support the argument for SATA.

Once the drive type has been decided, what is the preferred drive
configuration?
Mirrored system drives and RAID 5 data
OR
RAID 5 array for both system and data?
I am looking for around 2 TB

Any comments on the above opions appreciated.

Phil

27-Jan-10 12:36 PM

I always do a mirror on the system drive and RAID5 on the rest.

Regardless of what problams you may have had with your SCSI setup I still
consider SCSI more reliable.  The problem may be your particular hardware
brand or model,...or just bad luck.

I have seen a ton of trouble with custom built machines.  I have had little
to no trouble with machines from major vendors like Dell.  The worse I have
had to do with my Dells is update the Firmware on both the Controller and
the Drives (which should always be done anyway), and I might have had to
re-seat a drive one or twice.


--
Phillip Windell

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------

27-Jan-10 08:47 PM

In article <qY6dncKmXINC9_3WnZ2dnUVZ7vydnZ2d@eclipse.net.uk>,
phil@dropthespam.com says...

I would rather see you install 4 x 1TB drives in a RAID 0+1 or 1+0
setup, you get speed and redundancy.

Normally I would setup an OS partition for 100GB, since space is cheap
and running out of space is a PITA. Use the rest for your data.

As for SATA, SAS, SCSI.... SAS/SCSI perform well, SATA is still slow. If
you get a caching raid controller for the SATA you may not see the
performance difference with 20 users.

--
You cannot trust your best friends, your five senses, only the little
voice inside you that most civilians do not even hear -- Listen to that.
Trust yourself.
spam999free@rrohio.com (remove 999 for proper email address)

28-Jan-10 04:13 AM

As others have said, SCSI is still the best for server RAID arrays.

For the file server, I would RAID 1 the OS and RAID 10 the data

For the Exchange, you may want to consider RAID 1 for OS, RAID 1 for the
log files and RAID 10 for the database files.

I prefer RAID 10 over RAID 5 due to performance and redundancy...

--

Regards,
Hank Arnold
Microsoft MVP
Windows Server - Directory Services
http://it.toolbox.com/blogs/personal-pc-assistant/

29-Jan-10 04:59 AM

Thanks to all respondents

Plenty of food for thought there.

Phil

29-Jan-10 10:01 AM

People often choose RAID5 for the same reason.  What is the difference
between 5 and 10?

--
Phillip Windell

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------

29-Jan-10 10:51 AM

philwindell@hotmail.com says...


Raid 10 is a combination of raid 1 and raid 0, with both striping and
mirroring.  So you need at least 4 disks, and you only get 1/2 the
capacity (4x1TB disks gives you 2TB usable storage).

Raid 5 needs at least 3 disks, and uses the *capacity* of 1 of them for
parity and rebuilding, and will continue to run with one dead disk.
it is more space-efficient than Raid 10, but not quite as fast.

D

29-Jan-10 12:00 PM

In article <MPG.25ccce1481192d089896ba@news.conversent.net>,
ns_dkerber@ns_warrenrogersassociates.com says...

When a single drive fails in a RAID 10/01 setup you really do not see a
significant performance hit.


If you have a 3 or 4 drive R5 setup and a single drive fails you will
see a SIGNIFICANT PERFORMANCE HIT.

Disks are cheap, but many servers only provide 5-6 disk slots (in the
cheaper servers), so your options may be limited.


--
You cannot trust your best friends, your five senses, only the little
voice inside you that most civilians do not even hear -- Listen to that.
Trust yourself.
spam999free@rrohio.com (remove 999 for proper email address)

29-Jan-10 12:39 PM

spam999free@rrohio.com says...

You will when you start rebuilding the failed disk.



Only once you replace the failed drive and start rebuilding it.  If you
continue to operate with the failed drive in place, you no longer have
the redundancy, but the speed is not hurt.

29-Jan-10 01:13 PM

That's what I thought too.  Even with the debate over speed the difference
in speed (during *normal* operation) is so miniscule to not even be
speed was the bottleneck.  It was always the Network throughput that held
things up.

--
Phillip Windell

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------

29-Jan-10 01:31 PM

philwindell@hotmail.com says...

I have some highly disk-intensive processes that run in the middle of
the night that I have found are limiting my backup speed while the
network is nowhere near being saturated, but those kinds of situations
are going to be rare for most applications.

I suppose one situation where a failed HD in a raid array may cause
throughput issues, MIGHT be if you have a software raid instead of a
hardware controller.  That's just speculation on my part, though,
because I have never had the nerve to try software raid.

D

29-Jan-10 02:42 PM

In article <MPG.25cce77caeb589c39896bb@news.conversent.net>,
ns_dkerber@ns_warrenrogersassociates.com says...

Depends on the controller and the %CPU for rebuild - cheap controller
cards impact the performance, better ones do it without you feeling it
at all.


Yes it is, dramatically. Seen it happen on more compaq servers than I
care to shake a stick at.

--
You cannot trust your best friends, your five senses, only the little
voice inside you that most civilians do not even hear -- Listen to that.
Trust yourself.
spam999free@rrohio.com (remove 999 for proper email address)

30-Jan-10 01:47 PM

Hello,

I agree with all the prior posts : SAS or SCSI for RAID and definitely
Hardware RAID.

Important: use a GOOD raid controller, LSI, Adaptec, Mylex. Stay away
from cheapies. I have witnessed horrible experiences with low end SATA
drives and SATA RAID controllers even from well known companies (that
make CPU's and GPU's) where I have witnessed corrupt data when one
drive fails, clueless tech support personnel and buggy drivers and
product discontinuation w/o future support. Low end RAID controllers
bring headaches instead of preventing them.

The Adaptec and LSI controllers on Dell Servers sunning SCSI or SAS
have been VERY reliable for me. I have never had problems with either
and doubtful I ever will (knock on wood). I have 6+ year old models
out in the field  that have had failed drives. I replaced the drives,
rebuild, no problems, no lost data, no worries, no headaches. Worth
the $.

Good luck,

Miguel Fra / Falcon ITS
http://www.falconits.com

31-Jan-10 05:52 AM

RAID 5 is slower.

--

Regards,
Hank Arnold
Microsoft MVP
Windows Server - Directory Services
http://it.toolbox.com/blogs/personal-pc-assistant/