hi ya
comparing ide vs scsi..... an age old problem... ??
i say....in my opinion..
you cannot compare an 5400rpm ata-133 ide against a 15krpm scsi-3 u160..
( well at least definitly not a 5400 rpm 10GB against a 15K rpm 80GB scsi3)
- if you do compare ... use tiobench or bonnie...
for real life performance differences with real data ??
- not raw basic numbers comparson of "feature/characteristics"
- raw rpm speed by itself doesnt matter ...
- 7200rpm ide disks runs hotter than 5400 rpm ide disks :-)
- ata-33 ( 33MB/sec) vs scsi-3 (20MB/sec ) comparason doesnt matter ??
- its comparing different "numbers" ...
( but actual data transfer of the same test program is a
- comparing seek time of either ide or scsi when seeking from
outermost cylinder to innermost cylindery comparason is fair..
- if one disk is spinning at 5400 rpm... and the other is spinning at 15k
rpm ... guess which one will seek faster on the same cylinder ??
--->> if 7200rpm scsi-3 disks has 2MB of disk buffer...you can do a fair
--->> comparason with a 7200rpm IDE disks w/ 2MB buffer tooo
-- closest fair comparason as far as i can tell
-- to do tiobench and bonnie benchmarks
- if you have ONE ide cable with 2 disks on it... they both have
to share that cable
- if you have eight scsi-3 disks on one scsi-3 cable... they all have
to share that cable... ( 7 disks have to wait...while its data
is on the cable...
- 2 ide controller on the PCI buss share the same pci backplane
- 2 scsi-3 controller in the PCI buss share the same pci backplane
- i think we can tweek the comparson one way or another depending on
desired results ...
- negotiating and amount of data transferred on the cable once oyu
have controll of it is a major factor in how fast you can move
data from disks to memory or vice versa or disk-to-disk
- if one wants physcailly "hot swap" disks... scsi-3 wins hands down
- nobody has implemented a live "hot swap" ide disks ???
- write a 2GB files to disks and pull it out at the same time
- we will also ignore the fact that scsi disk drivers are built/written
differently than ide disk drivers...
- we will also ignore that the onboard disk controller on the disk
are different on the ide vs scsi3 drives
- transfer speeds are comparable ???
==
== http://www.Linux-1U.net/Disks/
==
40Mb/sec -- ultrawide scsi3 or wide ultra2 or ata-33 ( 33MB )
80MB/sec -- ultrawide2 scsi3 or ata-100 == ( 100MB )
160MB/sec -- ultra160 or serial-ata
320MB/sec -- ultra320
-- btw IBM 40GB and 60GB are pure junk !!! all the disks that failed
are IBM drives...
-- hott scsi disks are also sitting on my desk... higher death rates
of scsi disks vs ide disks as a ratio of number of numbers in use...
have fun comparing..
alvin
btw...the original poster did have 2 18GB scsi disks...
explicitly specificied as ibm xxx as oppsoed to seagate or other
vendors...
- there is no 15krpm ide disks ?? ...
On Mon, 25 Feb 2002, Petro wrote:
> On Mon, Feb 25, 2002 at 01:58:59PM -0800, Noah Meyerhans wrote:
> > On Mon, Feb 25, 2002 at 12:21:33PM -0700, Jason Majors wrote:
> > > Also, I'd recommend a 40GB or so IBM ATAPI hard drive instead of the
> > SCSI
> > > option. It'll cost you less and provide about the same access speed.
> > Maybe
> > > even faster access, if you get a 60 or 80 GB drive. Just make sure
> > it's a
> > > 7200RPM drive.
> > No way! Those drives are very much worth the money. How can you
> > compare a 7200 RPM IDE disk to a 10k RPM SCSI disk? IDE is cheap for a
> > reason. It's junk. Don't put junk in such a nice machine!
>
> There are several reasons that IDE is cheaper that SCSI:
>
> (1) Buffer sizes--I haven't seen any IDE drives have 2 MB or less,
> while comparable SCSI drives have 4 MB
> (2) Seek times--usually twice as high on IDE.
> (3) Rotational speed--usually higer on the more expensive drives.
> (4) Warranty period--IDE drives usually have a 1 year warranty,
> while SCSI tends to be 3 years.
>
> Now, look at the cost deltas. For what it costs to get a SCSI
> drive, I can usually get 2 larger IDE drives. With software
> mirroring, I can get at least as good a read performance, with
> write performance suffering only a little (if at all).
>
> And I've got a mirror for when I loose one.
>
> It's not about which technology is better--SCSI is clearly a better
> technology (we'll see what serial ATA brings), it's about which is
> more cost effective. I have several systems in my colo which have
> 300-500 GiB of storage in them, some of which (the 300 GiB systems)
> would have been inordinately expensive to do with SCSI (4 73 GiB
> scsi drives==Lotsabucks), and the larger (490GiB) systems would
> have been all but impossible--these are 5 drive 2u rack systems.
>
> I wish SCSI were 1/2 the price, then it would be easier to justify,
> but with the current price points, it's often cheaper to build 2
> complete systems off of IDE than 2 out of SCSI.
>
> --
> Share and Enjoy.
>
>
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