Hardware opinion: Slow SCSI or fast IDE

Hardware opinion: Slow SCSI or fast IDE

Post by nospa » Mon, 05 Sep 2005 17:25:41


I need to make a short term 3.12 (yes, that's not a typo) server.

The existing box is a 486 66mhz 128mb ram with a 2Gb SCSI drive and
10mbit card serving around 8 users. The box only has 16bit slots.

I could try to replicate the above or more easily grab a spare PIII
350mhz, 256mb RAM 100mbit PCI card with oodles of disk space on the
IDE drive.

Although I've always adhered to using SCSI drives for servers I
suspect that the faster IDE drive with extra cache memory available
will run rings around the older 486 machine.

What do you reckon?

--
AnthonyL
 
 
 

Hardware opinion: Slow SCSI or fast IDE

Post by Johnny B G » Tue, 06 Sep 2005 00:16:52

The message < XXXX@XXXXX.COM >
from XXXX@XXXXX.COM (AnthonyL) contains these words:






Unlikely to make a blind bit of difference. My first experience of
netware was 2.15C on an 8MHz 286 box (NEC PowerMate 2, as it happened),
with 600MB ESDI disk.

I upgraded the MoBo to a 386SX33 one and saw very little improvement.
Having upgraded to a 386 cpu based system, I was then able to ditch the
2.15C and install 3.11 which I quicly upgraded to 3.12 which I was using
up until a few weeks ago when I replaced it with a Debian based samba
server.

After installing 3.12, I regularly upgraded the hardware through 486,
SKT7 P166, SKT370 Celeron 466 and (briefly) skt370 p3/500 and finally
back down to an under volted and underclocked skt7 K6/500 (running at
250MHz) reducing the power consumption to a mere 29 watts with a single
250GB Seagate drive.

In all that time and in spite of upgrading from the on-board udma33 IDE
to a Promise ata100 lba48 controller card, I never saw the write
performance go above 1.4MB/s using 100Mbps NICs. The read performance
was only about 4 times faster at best.

I gave up on this NOS on account of the 'slow by design' writing
performance and also on account I couldn't use hdds larger than 120GB in
spite of all my efforts at finding a solution to the speed and size
limitation issues. The 'vapourware' claims for no disk capacity limits
obviously only applied to, as yet, undeveloped and radically different
future versions of Netware. :-(

If 'oodles of disk space' is only going to involve drives smaller than
120GB, ok, otherwise forget it with 160GB and bigger. If the MoBo
supports LBA48, don't expect faster than 1MB/s writes regardless of
whether you're using 100 or 1000Mbps NICs. :-(

HTH

--
Regards, John.

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Hardware opinion: Slow SCSI or fast IDE

Post by nospa » Tue, 06 Sep 2005 20:57:02

On Sun, 4 Sep 2005 16:16:52 +0100, Johnny B Good



Stumbled on my 2.12 (Acer OEM) disks the other day and recall
discussions about ESDI or SCSI. Our first was ESDI also :)


I'd agree that the processor would not make much difference as it was
not the limiting factor in file and print sharing.


You don't seem ever to have gone SCSI. How many users?


I though Netware 5 could handle terabytes -
http://www.yqcomputer.com/



oodles relative to the existing 2gb drive :) like I mean 6gB


--
AnthonyL
 
 
 

Hardware opinion: Slow SCSI or fast IDE

Post by Johnny B G » Wed, 07 Sep 2005 03:01:51

he message < XXXX@XXXXX.COM >
from XXXX@XXXXX.COM (AnthonyL) contains these words:








Four maximum, it was a "Home Network" setup to save me having to
upgrade the hand me down PCs' hard disk drives my kids were using (Ah,
the joys of networked Doom! :-)

SCSI never impressed me performancewise compared to their cheaper IDE
cousins. In fact (for desktop PC use) they were rather a let down
performancewise size for size. There was also the issue of heat and
noise (and excessive power consumption) to consider. For my needs, SCSI
just didn't cut the mustard.



I don't doubt this is true, after all, 3.11 predated win95 by a good 2
years and was obviously able to support drive capacities well in excess
of what was then currently available as opposed to dos which kept
trailing behind these capacity limit increases.

You've got to hand it to Novell for creating a NOS that only suffered
this fate after 10 years of hard disk drive development.



As I said, I don't think you'll see any improvements then. The
bottleneck _isn't_ the disk drive. Of course, I never tried it with any
fancy SCSI HBAs and noisy SCSI drives so I can only comment on IDE
types. It just struck me as rather strange that despite 'modern' (FSVO
modern) ATA100 controllers and Novell drivers to match, the 40MB/s or
faster write speeds of 80 and 120 GB drives was all for naught. :-(

If I could get my hands on a very cheap (say 5 user) version of Netware
5, I'd install it in a shot. The SAMBA server only replaces that old
Netware 3.12 setup on account it supports drives bigger than 120GB and
brings the writing speed over the 100Mbps LAN closer to the 8.25MB/s I
usually see win2k box to win2k box. The Debian based server gives me
about 7.8MB/s write speeds which is over 5 times faster than I was
previously getting.

The only downside I've noticed is the slower (most definitely uncached)
reading of directory trees from the server. I have a CD's worth of mod
files (3600 odd tunes in some 20 odd directories) stored on the server
and whenever I load ModPlugPlayer with the full playlist, it takes about
15 seconds to load B4 it starts playing as opposed to the 4 seconds it
used to take with the Novell server setup.

Considering that Linux is free and Novell netware costs hundreds of
pounds, that's a downside I can live with (and possibly fix :-).

--
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Hardware opinion: Slow SCSI or fast IDE

Post by nospa » Wed, 07 Sep 2005 19:03:26

On Mon, 5 Sep 2005 19:01:51 +0100, Johnny B Good




In "single user" type mode it wouldn't impress. SCSI only scores when
there is concurrent multi-user access and Novell also then scores
because of its excellent disk caching. Hence my original question.

Cheers


--
AnthonyL
 
 
 

Hardware opinion: Slow SCSI or fast IDE

Post by Johnny B G » Thu, 08 Sep 2005 07:51:02

The message < XXXX@XXXXX.COM >
from XXXX@XXXXX.COM (AnthonyL) contains these words:






If you're considering setting up with a SCSI HBA and a 6GB SCSI drive,
you might discover the secret to getting sustained data transfer rates
that can match the drive's capabilities, i.e. 2 or more times faster
than the poxy 1 to 1.4MB/s I was seeing with drives perfectly capable of
30 to 40 MB/s. The performance hit over a 100Mbps network during read
operations wasn't as crippled (I was seeing around 4 to 6 MB/s
transfers).

Actually, now I think about it, when I had 512MB of ram, I was seeing
similar 4MB/s writing rates over the wire until the disk writing cache
filled up (after about 400MB's worth of data had gone over). What got me
was the enforced 1MB/s write speed to disks quite capable of 30 to
40MB/s sustained write speeds (using on-board udma33/66 IDE ports, the
promise ata100 controller only boosted things by a mere 40%).

I had the latest novell drivers for the relevant chipsets involved (and
I got to try quite a few!), but there seemed to be a hard limit at 1MB/s
(1.4MB/s in the promise controller case) which seemed to have absolutely
nothing to do with disk drive performance.

If you're going to set up a SCSI based system, I'd be interested in
your experience, assuming you're going to be using CAT5 at 100Mbps.

--
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Hardware opinion: Slow SCSI or fast IDE

Post by Johnny B G » Fri, 16 Sep 2005 22:38:00

The message < XXXX@XXXXX.COM >
from XXXX@XXXXX.COM (AnthonyL) contains these words:






Second follow up:

In short, I can only comment on my experience which never involved scsi
drives in the netware box. It seemed to me that there was a hard limit
of 1MB/s (1.4MB/s in the case of the promise controller) when writing to
the disk regardless of the fact that the drives could quite easily
perform 30 or more times faster than this.

I know this was to do with the actual disk writes since I could see
much faster data transfers over the wire until the disk write cache
buffer filled up, whereupon the rate would drop from the 4MB/s or so
speed down to 1MB/s (or 1.4MB/s in the promise controller case).

When you do set up that server (with scsi drive), I'd be interested to
know if using scsi gets around the 1MB/s write speed limit.

--
Regards, John.

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