Re: Linux Installation with SCSI Drive
Tim Kelley <tim@it.kpt.cc> writes:
> On Monday 06 September 2004 00:00, Ronald wrote:
> > I often try out (installing) Linux distributions, so
> > this is an I/O intensive operation (writing to the drive).
> >
> > Would using SCSI drive significantly improve the installing
> > time? (halve it?)
>
> Yes, from CD/DVD of course.
Are there any DVD SCSI devices? AFAIK there are IDE to SCSI adapters
which attach your DVD to a SCSI bus.
Unless, you are carrying some older SCSI devices (I have a pair of
Plextors which still work just fine), I would just attach the CD/DVD
to the IDE system.
> > FYI currently I use Seagate 7200.7 80 GB and to get
> > full 3 GB install takes around ~10 to 20 minutes.
>
> Hmm, a full (everything that doesn't conflict i guess) install of debian is
> more like 12GB! This must be woody ...
>
> > Motherboard is Abit KG7-Raid which doesn't have inbuilt
> > SCSI adapter, so I have to buy a separate adapter.
> > CPU is Athlon XP 2400+ with 512 MB RAM.
>
> > And the drive I want to get is probably
> > Seagate Cheetah 15K.3: 18 GB, 15,000 prm Ultra320 SCSI
> > http://www.seagate.com/cda/products/discsales/marketing/detail/0,1081,619,0
> >0.html
You do realize that the usual PCI slot is limited to 120MB/sec (and
real throughput is somewhat less). Unless you have 64 bit or 66MHz
PCI, there is *no* point in U320 *at* *all*. Stick with a U160
controller.
Also, your typical SCSI disks are not that much faster than typical
IDE disk (of same model year). The follow is just typical and does
not necessarily follow from the interface SCSI/IDE but are features of
the disks you will find -- caveat is here to make explaination easier.
The SCSI disk spins faster but has a lower bit density. The SCSI disk
will have a fast seeking arm and use a smaller disk to reduce arm
travel distance. This means that access times for the SCSI disk are
up to twice that of the IDE (less time to wait for sector to spin
around to you, less time for head to move into position).
On the other hand IDE offers greater total capacity.
The higher density of IDE designs is offset by the slower rotation
speed which means that sustained transfer rates are close.
SCSI costs up to 2-3 times as much as IDE per disk. Also expensive is
all the SCSI infrastructure, controller card, cables, termination,
SCA cage, etc.
SCSI is totally *not* worth it for a single disk system. What SCSI
does allow you to do is stuff many more hard drives into your system
than IDE will. More spindles = less having to seek. I put system on
one disk, my home on another, swap on a third. Now, I can launch and
app (disk1), have it read data from my home (disk2) and push some
dormant application onto swap (disk3) with a minimum of seeking.
RAID5 is also done with SCSI, but this is going to be expense extreme.
> Really it probably isn't worth it. My system is all SCSI (hardware raid and
> SCSI dvd and cdwriter) and although it is very responsive and never jerky (I
> mean never), it really doesn't justify the cost on a home pc. I assembled a
> Frankenstein system though, of somewhat older equipment that was cheaper
> (most from ebay).
I like <URL:http://www.centrix-intl.com> for some cheap surplus server
gear. Be aware that some of their offering is a bit ancient these days.
> If you mobo has onboard ide raid I would just go with that, unless you got
> money to burn.
Agreed.
> If you do I would get an adaptec or bus logic controller though, the linux
> drivers are very good.
I think you mean LSIlogic (formerly Symbios and before that NCR)
rather than Buslogic (now Mylex I believe). The LSI controller is
likely to be a fair bit cheap than the adaptec although both are fine
controllers with good linux driver support.
--
Johan KULLSTAM
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