RAID recommendations

RAID recommendations

Post by John DeRu » Sun, 05 Jul 1998 04:00:00



Looking to place a raid system on a RedHat 5.1 server.  Does anyone have
suggestions or positive experiences about particular raid systems or
controller cards?  I' appreciate any pointers.

Thanks,

John

 
 
 

RAID recommendations

Post by Gregory Trav » Wed, 08 Jul 1998 04:00:00




Quote:>The DPT adapters are extremly fast and the driver is rock solid. Used to
>run our web server with 200.000 hits a day on 200 Mhz Pentium with 192 MB
>ram and DTP 3334 UW with 64 MB of cache. Go for DPT at www.dpt.com

The DPT adapters are good ones - reliable and well supported under Linux.

However, while evaluating them we found that they are performance-limited
by the onboard 68000 processor.  In particular, we could not pump out
more than about 8MB/s in a RAID-5 configuration using 5 Quantum Alpha
drives.  We got about 13MB/s in a RAID-0 config with the same drives.

We also tried the ICP GDT series RAID controllers.  They are also well
supported under Linux and appear to be quite robust.  Using the same
drives in the same RAID-5 config, we got over 14MB/s sustained read
using the ICP controllers.  Not great, but better.

greg
--
greg travis                     "The coffee shop piano plays toe-tapping jazz,

http://www.prime-mover.org/             --- Microsoft, in "The Future is Today"

 
 
 

RAID recommendations

Post by Henrik Bremersko » Wed, 08 Jul 1998 04:00:00


The DPT adapters are extremly fast and the driver is rock solid. Used to
run our web server with 200.000 hits a day on 200 Mhz Pentium with 192 MB
ram and DTP 3334 UW with 64 MB of cache. Go for DPT at www.dpt.com

/henrik


> Looking to place a raid system on a RedHat 5.1 server.  Does anyone have
> suggestions or positive experiences about particular raid systems or
> controller cards?  I' appreciate any pointers.

> Thanks,

> John

 
 
 

RAID recommendations

Post by Chris Ada » Wed, 08 Jul 1998 04:00:00



Quote:>The DPT adapters are good ones - reliable and well supported under Linux.

>However, while evaluating them we found that they are performance-limited
>by the onboard 68000 processor.  In particular, we could not pump out
>more than about 8MB/s in a RAID-5 configuration using 5 Quantum Alpha
>drives.  We got about 13MB/s in a RAID-0 config with the same drives.

Which DPT adapter were you using?  The SmartRAID IV (3334) has a 68040
that can pump a good bit of data in my experience.
--

System Administrator - Renaissance Internet Services
I don't speak for anybody but myself - that's enough trouble.
 
 
 

RAID recommendations

Post by Gregory Trav » Wed, 08 Jul 1998 04:00:00




>>The DPT adapters are good ones - reliable and well supported under Linux.

>>However, while evaluating them we found that they are performance-limited
>>by the onboard 68000 processor.  In particular, we could not pump out
>>more than about 8MB/s in a RAID-5 configuration using 5 Quantum Alpha
>>drives.  We got about 13MB/s in a RAID-0 config with the same drives.

>Which DPT adapter were you using?  The SmartRAID IV (3334) has a 68040
>that can pump a good bit of data in my experience.

That's the controller we were using.  Onboard 68040 with 64MB of RAM for
cache.  Diskperf, Bonnie, and "time dd ..." all demonstrated sustained,
sequential, read performance of about 8MB/s with a 5-disk RAID-5 array.  We
got a sustained 2MB/s write performance in that config.

The ICP GDT controller delivered roughly twice the sustained performance
of the SmartRAID IV controller - 14MB/s sustained read and 4MB/s sustained
write.

Note that we were using 5 identical Quantum Atlas drives.  Previously we
had benchmarked an individual Quantum, through an Adaptec 2940UW, at
roughly 10MB/s sustained read or write.  Thus the theoretical maximum
sustained transfer speed of our RAID-5 array should have been in the 40MB/s
read/write range.  The ICP controller got 35% of that and the DPT controller
got 20% (for reads).

That we got the DPT up to ~13MB/s in a RAID-0 config strongly suggests
a CPU bottleneck on the DPT card.

A conversation with DPTs technical department confirmed that the performance
we were seeing was to be expected.

greg
--
greg travis                     "The coffee shop piano plays toe-tapping jazz,

http://www.prime-mover.org/             --- Microsoft, in "The Future is Today"

 
 
 

RAID recommendations

Post by Eivind Bakkestue » Fri, 10 Jul 1998 04:00:00


Well, 14MB/s isn't so great anymore - the latest batch of 7200RPM IDE
disks get very close to this.

I have a Promise Fasttrak IDE RAID controller in my machine and two of
the latest Seagate Medalist Pro 9GB disks; I get a max sequential
reading around 25MB/sec. And that is under NT 4.

If only Promise would make a Linux driver... :-/




> >The DPT adapters are extremly fast and the driver is rock solid. Used to
> >run our web server with 200.000 hits a day on 200 Mhz Pentium with 192 MB
> >ram and DTP 3334 UW with 64 MB of cache. Go for DPT at www.dpt.com

> The DPT adapters are good ones - reliable and well supported under Linux.

> However, while evaluating them we found that they are performance-limited
> by the onboard 68000 processor.  In particular, we could not pump out
> more than about 8MB/s in a RAID-5 configuration using 5 Quantum Alpha
> drives.  We got about 13MB/s in a RAID-0 config with the same drives.

> We also tried the ICP GDT series RAID controllers.  They are also well
> supported under Linux and appear to be quite robust.  Using the same
> drives in the same RAID-5 config, we got over 14MB/s sustained read
> using the ICP controllers.  Not great, but better.

> greg
> --
> greg travis                     "The coffee shop piano plays toe-tapping jazz,

> http://www.prime-mover.org/             --- Microsoft, in "The Future is Today"

--

<<<<<<------------->>>>>>>
Eivind Bakkestuen was here
           ***
"I was the second gunman
 on the grassy knoll."

 
 
 

RAID recommendations

Post by Brion Vibbe » Fri, 10 Jul 1998 04:00:00



> Well, 14MB/s isn't so great anymore - the latest batch of 7200RPM IDE
> disks get very close to this.

> I have a Promise Fasttrak IDE RAID controller in my machine and two of
> the latest Seagate Medalist Pro 9GB disks; I get a max sequential
> reading around 25MB/sec. And that is under NT 4.

> If only Promise would make a Linux driver... :-/

I'm not so sure they care... I'm attaching a response I got from asking
them about it. :(

Note that there is another low-cost alternative, which is to use the
Linux software RAID driver and a regular Ultra-DMA controller. Probably
not as good as the `real thing' but should still be good; I've heard of
18MB/s reads with a commodity TX motherboard's controller and those
probably weren't 7200 rpm disks.

[ Attached Message ]

From:
To:
Date: Thu, 9 Jul 1998 10:17:07 -0700
Local: Thurs, Jul 9 1998 1:17 pm
Subject: RE: FastTrak and Linux support
You're correct, I'm sorry to say there are no drivers for Linux at this time or in the near future.

Moses Lee
Promise Tech Support

-----Original Message-----

Sent:   Friday, July 03, 1998 7:17 PM

Subject:        FastTrak and Linux support

I have had a Promise Ultra33 in my computer for a year, and have been
very satisfied with its performance. I am considering stepping up to a
FastTrak RAID controller in the near future for even better performance
since I am a film student and will be editing digital video.

There is only one problem: I am a Linux user, and there are no drivers
for the FastTrak available for this high-reliablility, high-performance
operating system. A competing SCSI product is not an attractive option
due to the cost, but it could be my only option unless support for the
FastTrak becomes available for Linux.

Promise has the choice to do one of four things:

1. Release the necessary information to Linux developers who will then
be able to create a driver with no effort or cost on Promise's part. I
have heard that Promise is reluctant to do so because `secret'
information might be released which would harm the company's position,
which leads us to:

2. Create a driver in-house and thus need to release only that
information that is in the driver itself (and could thus be determined,
albeit slowly, by reverse-engineering existing drivers for other OSs)
or:

3. Hire a contractor already familiar with Linux internals to produce
the driver for you under NDA (alas, I am not competent to do such a
thing myself or I would offer). The last alternative is:

4. Do nothing and lose sales, breed discontent among customers who
belatedly discover that they are not allowed to mix high quality
hardware and software, and generally be very unproductive for everyone.
(This is the current situation.)

Please do one of the first three - your company will benefit, your
customers will benefit. The only people who will lose are your
competitors who would lose the Linux market to Promise.


Author and maintainer of the Linux Ultra-DMA mini-HOWTO

 
 
 

1. RAID recommendations

I'm running SCO 5.0.5 and I currently have an Adaptec aha-2940 scsi adapter.
I'm going to install a RAID card.  I'm considering a DPT Decade PM1564U3
Ultra160 for $461 or a DPT Centruy PM2654U2-R-1 Ultra2 for $670
Is it worth the extra money for the Century?  Its a slower speed being
that it's only Ultra2.  I'm going to get two Seagate ST39204LW Cheetah 18XL
9.2 Gbyte drives.

My primary reason for getting the RAID is disk mirroring.  Secondly my
reason is I hope to speed up our payroll system.  We are using Abra Suite,
which uses a Foxpro database that runs on a Win98 PC, but uses the network
drive of my SCO server.  This is very disk intensive and really slows the
system down while the payroll is processing.  Apparantly a lot of data is
being read and written to the drive. It really works hard.

What do I do with my current tape drive, it has a 50 pin connection.  Can this
be hooked to the RAID controller?  I think it only supports 68 pin.  Or do I
leave my aha-2940 in there to control the tape drive?

--

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